Why do women give you more chance when you're older??

Your declining sex drive to the point where it's a challenge for you to deliver sexually is probably the canary in the coalmine.
The early warning signs of your blood vessels getting clogged up. Most likely mainly due to consumption of junk and semi-junk food and drink over the years.
The good news is that making significant improvements to your nutrition will slow down, or possibly halt or maybe even to some extent reverse this process.
With the right eating and drinking habits you can expect to be sexually active until shortly before your death. Whenever that is. 80's, 90's, 100's. OK you won't be as active then as you were when you were 21, but you would still be active enough.
Mental and emotional strength is attractive to women. Mental and emotional weakness is unattractive. Good communication skills are attractive to women too.
It sounds like you've been doing the right things to improve these aspects of yourself. And now you're reaping the rewards.

In what seems like a cruel irony, the years when your sex drive is high are wasted as women don't find you mature or established enough, they seem to like older guys. I've gone through the weird experience of women being showing more signs of being interested in me as I aged. Unfortunately there is a small window of opportunity you gave to take as now my sex drive has declined and I'm 44 I feel past it but the outward signs are a good or better than they have been in the past. This is somewhat
melancholy and depressing. I couldn't deliver sexually enough even though I get signs if interest and find women attractive.
Does anyone else experience this phenomenon as an older or younger guy?
Can any women explain why they show more interest as you age?

as a woman i have no idea what youre talking about (im 23)
my bf is 25 and is both mature and immature, he has the perfect balance. my ex was a year younger than me and very immature, and it really ruined our relationship because i wanted serious and he just wanted fun. I think thats maybe what you mean, women want more mature men because most women take a relationship very seriously as an adult - its about stability and someone who will commit to you and want to put their all in to show how much they love you, but theres nothing to do with sex drive. if anything a lower sex drive probably makes you more mature because youre not going to only be in a relationship for the sexual aspect, you can actually think outside that and be in love for more than that, or without that especially in an older age - you dont need a sexual partner, you want a life partner. thats what i want right now (but we still have those hot moments bc were both young and you know want that lol but its not just that).