It only gets better with age, buddy. That is, as long as you take care of yourself. If you're not doing PT and watching your diet now, you need to start. You may not believe it, but you will age a lot quicker in your thirties if you don't take care of yourself. You need to establish positive habits now, so your metabolism and your body doesn’t have to play "catch up'. The older you get, the harder is to build muscle and lose weight, so get a head start on it. Of course, you may be a chiseled machine and if so, keep it up. The only birthday to worry about is your last one, and even that one's not worth worrying much over.