As you grow older, you would still retain all the information you've learned over the years. But, you'd still remain sharp as a tack, ready to retain more information, and be able to receive new technology as it is introduced. Not only that, but you'd still understand that your body is getting older and you can't do the things that you used to anymore.
Plus, dementia is a thing and it is scary as fuck to me.
All you guys choosing the physical option are crazy - imagine if you have the body of a 21 year old but your minds regressing and you're getting slower and slower. Completely agree with the person above mentioning dementia. Mind for me