vhehn, excellent post.
They say, look at your girlfriend's mother to get an idea of where your wife is headed, and that seems to be so (she'll of course be looking at your dad's balding head and potbelly) as you're expected to get older too. I started working out in my late 30's and by 40 was in better shape than I was in my 20's and I wasn't that bad in my 20's. But as you get older, it takes its toll and to offset that, you should excercise and weight train a bit to keep your body as youthful as possible as you sail into older age, just because once you age, there's no turning back and you need to stay as resilient as you can.
I have noticed that the majority of marriages occur to people in their 20's, by virtue of the fact that all their friends get married and they start to get pressured to do so themselves. so, they end up marrying whoever they are dating at that time. That's not the way it should be. They have not discovered themselves yet and settled on their wants, likes and dislikes enough to commit themselves to another. Wait until you're a bit older and know what you're looking for in a mate, not a date.
They also say, and you may want to keep this in mind if you find yourself in this situation, that it's better to marry someone who really loves you, then it is to marry someone who doesn't but whom you really love. I think it was Marilyn Von Savant who wrote that, and she's the one if not the world's highest IQ person.
You should enjoy life and spend your money, but with an eye toward your future. Using time and compounding, you have it all before you to utilize wisely to end up with a fortune for your later years. If you don't die first, that's exactly where you'll end up someday, and you'll be grateful you took advantage of your lifespan to accumulate and build wealth so that you're not stuck at retirement still having to make ends meet or not live your dreams. I would think. Insofar as careers, do what you love to do, because otherwise your stomach will churn in knots when you have to go to work. It will eat away at your happiness. Your job/career shouldn't feel like work to you. This is your life, do not wait for the next one.