Approaching 50? Youngster!
Just enjoy it. I'm not one of these "I'm never going to get old types, and therefore I still need to beat everyone everytime". Never have been. It's not about that for me. I've had the opporunities to ride quite a few different places in the world, some self contained loaded touring, others supported with a nice road bike. It's all enjoyable. I don't train to ride. I just ride. I might do a couple of tt's this year... maybe, not because I need to prove myself, but because it's fun. And even as we age, cycling is just something you can do regardless of whether you're as fast as you used to be. Plus, I like working on bikes almost as much as riding them, so it's a great hobby to have, in all kinds of ways.
Of course, if you are one those "types", then I guess you'll just have to learn to deal with aging and work harder and harder, rest more to recover. Probably not the response you're looking for, but it seems to be the most obvious one. However, there's a lot of 50 somethings that can still kick ass at many levels of racing, so if you're one of those, then more power to ya.
Mandelbaum! Mandelbaum! (if you've ever seen the Seinfeld episode where Lloyd Bridges plays the geriatric fitness freak, you'll get that reference).