Hi,
according to my first teacher, I was too old at the ripe old age of "20". First thing she asked was my age, even before I had a chance to sit down at the piano.
Did a lot for my confidence, I was nervous enough as it was.
Heck , I didn't want to become a concert pianist, I just wanted to learn to play some simple tunes for self amusement.
I learnt to read & play despite her
( albeit very poorly ) haa haa.

I found the Hanon exercises great. They really built up independant finger strength.
I think the book I had originally was the Hanon 101 exercises?? They were played over 4 octaves from memory. I found a more simplified version a few years back, it was based on 2 octaves, & didn't have the full set of exercises.

best wishes
Rikki