First, I join the others in praising you for your ambition and excitement on learning to fly. Welcome to aviation. Learning to fly is really learning two things: A lot of new knowledge (facts, theories, rules) AND a new SKILL (flying the airplane). I sense you will not have much difficulty with knowledge. BUT, although you can do it, you will have a harder time with the SKILL portion than someone who is younger. Before you DISMISS ME, let me say that I'm much older than you (67). Although I learned to fly (private pilot) in my twenties, I didn't advance in my ratings until I was in my fifties. When I was 62, I decided to go for the airlines and got my multi-engine and multi-engine instructor ratings. At 63, got hired by the largest Regional and got my ATP and type rating. So, I know what it takes and I know what it is like to be old.
Flying is very much like playing a musical instrument. If you play, you know there is knowledge (theory, reading music) and skill (actually playing the instrument). The skill portion requires the brain to re-wire itself and form new pathways so that you can play without actively thinking. This is necessary because you will have to focus on reading the music, conductor, etc. In flying, it's position, air traffic control, situational awareness, etc. Like recovering from injuries just take longer as you get older, the brain takes longer to form these pathways. So, it will take more effort, both in terms of energy and duration. But you CAN do it. Just don't quit.
In my new hire class of 30, 5 of us were older than 45. I was at least 10 years older than the next younger guy. all of us struggled significantly more than our younger colleagues. All of us made it through the classroom training. Only two of us made it through sims and IOE (initial operating experience) which is in-cockpit training. SKILLS training. There rest didn't make it because they ran out of energy or couldn't put out the effort or just got discouraged.
This is getting long, so I'll add more in subsequent posts.