Nice piece. I have some suggestions that may help you create a more dramatic and interesting read however.

The first is, the old adage, show don’t tell. In several places you sum up complex actions with only a few words.

In a tone of disbelievement she said," When do you do this?"

I know we all know what it means, and how someone acts when in disbelief, but as a reader, it’s feels a bit cheap when the author just flat out says that’s how they acted. Instead think about how people act when they are in disbelief. Little motions are alright. Like how pople move their eyebrows, or do a double take, even the simple twist of their shoulders.

“When did you do this?” She said, her eyebrows rising to full attention. Like always she never believed me.

Show, don’t tell. Keep that and mind and this has some good potential.

Secondly, some formatting changes might make it a more dynamic read. For example, when people are talking, most of the time you can get away with having no speech tag, or just having the line on its own line. For example

My mom said,"Oh yea you do too work out like them."
I was really confused. I had been working out on a regular basis for at least twelve years. "Uh, I exersize."

Could turn in to:

“Oh yeah you do work out like them”
“Uh, I exercise”
I was really confused. I had been working out on a regular basis for at least twelve years.

In a short piece like this, we should beable to easily identify who is speaking based off the tones, and what  each person is saying.

If its clear what’s happening already* there’s no need to restate the obvious things such as “I said, She said, Mom said,” ect..

Keep up the good work!

* This is not a hard fast rule. Though I use it as a negative, for a first draft you should always assume that no one will understand what your saying and should include as much information as possible.

Nice work. You have a lot of grammatical errors and fragments, but they don't take too much away from the overall story. This seems more like a Realist piece than anything. A few of your ideas are confusing, subtle, but I think they don't effect this in any way. Keep up the good work. I recommend you read William Dean Howells or Gustave Flaubert. They'll give you ideas how to make this piece better. Do the best you can; stories take time to develop thoroughly.

 I enjoyed this writing. It was short and simple which is so much easier to stay focuses on everything that is going on. i like that i can relate to this i have conversations like that all the time with my mother and they just drive me nuts! i like writings to be simple and almost as if your talking to to a friend, it makes it personable and i can easy say i relate to it which makes me want to read more of your work. Good job!

Jenny - I lost my previous critique, so I will be very concise.  Please do not think I'm rude, I just spend some time on it and now will do my best to rewrite it!

First, you do a great job with dialogue.  It seems very real and you've been able to capture the way people speak.  I also enjoy how you've caught a moment that may have otherwise been passed and overlooked. 

Another reviewer said to show rather than tell.  I think this is a great thing to keep in mind, however, the reviewer used the phrase, " In a tone of disbelievement," (it should be disbelief) for his assertion, and I somewhat disagree.  While it is great to show in this case I think it is more important to show in instances of physical description. 

For example: 

You can see the muscle tone in my stomach.

This would be a great time to show rather than tell.  When it comes to descriptions of emotion, it is much more difficult to show and I say focus on the basics and work your way up.  I'm very bad at showing emotion in my writing and some authors will even ignore trying to show emotion altogether.  It is often a matter of preference. 

The ending works for me.  However, I might add some clue as to what the narrator thinks of the grandmother's sense of humor (or lack thereof).  That way, it gives it a well-rounded and thought out ending.  It would add to the wittiness of it!

Also, the first sentence shifts tenses:

I went to the store with my mom. She is in a wheel chair and needs someone to go with her most the time, so she can get things from higher places.

I shift tenses all the time, so I'm kind of surprised I caught it!  This is an easy fix.  I like doing things in the present tense, especially with dialogue, so choose your tense and go with it!

Thanks again for sharing this with us!

 Jenny,

As a catchall I enjoyed this piece. The voice feels comfortable in the pieces brevity. 

In your work description you noted that it was about a conversation.  The conversation seemed to reside more within the narrators mind than it did between the narrator and her mother.  I like that framework as a sort of 'story within a story' style.  However, as it stands I don't feel that the story of the mother and the narrator going to the store is a strong enough frame.  Everything that the mother contributes to the outiside conversation with the narrator has a small or one dimensional effect on the conversation the narrator is carrying within herself.  I would like to see the narrator reflecting on the physical aspects of the piece (the act of shopping, of being in the presence with the mother, of speaking with the mother) in a deeper more meaningful way and not simply the tightness of her abs. 

The tone of the story changes somewhat significantly as I moved through the story but the narrator gives me little to work with by way of interpreting the motive or means of the shift.  For me the change was perceived by way of the narrators reaction to the mother's comments.  The first thing the narrator responds with

                    "I told her,"It'd just be easier to eat what you want when you're hungry and drink a ton of water, than to diet. I can't diet. Ya know, I may eat like my family, but at least I don't work out like them."

Is much different from the last interaction she has with her

                     "I didn't find that funny, but I gave a little "ha", so that would be the end and it was."

At the start of the story the narrator is much more willing to carry on a conversation with the mother and by the end she ends it by implication.  However I am not sure why.