You'll be fine!
As I helped to care for my father in his last years, I had no problem remembering all he had ever done for me.
I only wished I could have done more.
I wasn't "ready" but it didn't matter. What more can you do for a loved one than your best.
He deeply appreciated that all his children cared enough to help, he was very embarrassed that we had to help him do things he could no longer do himself, but it all worked out.
It is good that you are helping your mom, but remember you aren't supposed to do it all, get some help, take turns, don't wear yourself down.
If you are always tired and grouchy and sore with mom, the experience won't be good for anyone.
Rob
Waiting for "someday" will leave you on your deathbed wondering why you didn't just rearrange your priorities and enjoy the time you had, instead of waiting for a "better" time to come along...