Memory Loss...What Age is too Young?

Should I be worried that my 5 year old already suffers from memory loss? Thomas swears that he has never been able to remember the small stuff, and I always just shook it off as a "man excuse"...for those of you who don't know, that is a real phenomenon! Most every night (I like to think so at least) I cook dinner, and we all sit down at the table together. After we dig in, I start the usual conversation of "What did you do at school today?" To which TJ's answer is usually "umm....ummm....ummmmm, I don't remember." This continues for a minute or so, until I get tired of hearing "umm." Then, I turn to the direct line of questioning.

Me: "What letter did you learn about today?"

TJ: "Ummm...P."

Me: "What sound does 'p' make?"

TJ: "pa pa pa."

Me: "Did you go to PE today?"

TJ: "Yeah, but we didn't get to outside...it was still wet!"

Me: (No kidding, really, I couldn't tell!)

Well, I guess that was a little better...but, day after day of pulling teeth to get out of him what he does each day is mind numbing and obviously he thinks the same. Last week on the way home, and I had not even mentioned school, he says

TJ: "Mom, I really want a photo-camera."

Me: "A photo-camera. Ok, maybe the Easter Bunny will bring you a little camera."

TJ: "But Mom, I need one now. And not for pictures...for movies."

Me: "Ok, why do you need one now?"

TJ: "So I can photo (video) myself at school to show you what I do every day...that way you don't ask me EVERY day!"

Lack of "memory brain cells"... I don't think so!