I SO enjoyed reading your post! Good for you, is all I can say! I am not a Grandmom, never was a body-builder, and may be a little bit younger than you...but I RELATE to you completely and felt a surge of "WOW...I am not the only person in this world that feels like I feel"!
I am with you 110% so you DO IT and you make your footprint back to who you wish to be in the "here and now".
Please write me if you need support (or feel like blowin' of steam)...I am SO where you are right now, it's unreal :)