Hehe, I feel ya bro. Ever since I turned 20, I thought it was all over, I grew desperate to make up for lost time, someone caught up in the idea that life ends at 25 and I better be settled down by then.
Relax buddy, you have plenty of fun years left, maybe when you turn 50 you should be thinking about settling down (or find a younger woman? My dad did...). You'll still be in your prime by the time you hit 40 my dear friend.
Don't worry too much about if (you probably will though, the above wisdom is the kind that only comes with age

), just make sure you have every ounce of fun you can squeeze out of every day, every week, every month, every year.
Oh, and the idea that there is nothing to look forward to when you graduate is just downright silly. That's when you get your awesome job, which gives you money for all the things you've ever wanted!