^You can still play Pokemon if you have those things going on.
I'm 22. I just graduated from a very good university and now have a full time job. I also have a boyfriend that I've been dating for 4 years in November and I try to find time on weekdays to walk a mile for exercise. I have friends who play and don't play Pokemon. My other hobbies include traveling (gonna try to plan a trip to Japan next year, and Australia the year after), the PS3, and baseball. I'm in the process of getting a dog too. And maybe a boat.
Regardless of all of this, I still play Pokemon. I may not be a good example right now because I'm selling off most of my collection, but not because I feel I'm too old for the game, but because I don't like the metagame much right now.
See, when you start eliminating hobbies because of 'adult' concerns, you age, and you stop enjoying life. I'm dead serious. Earlier this week I got a text from one of my coworkers saying that he wanted to go to this get-together in the weekend because he felt his life was too adult. When I asked him why it felt so adult, he told me it was because all he did was go to work, hit the gym, and sleep. You don't want to end up like that, it's so boring.
Also, when you start eliminating hobbies to focus on what life deems important, you're hurting yourself professionally. My junior year of college I was taking extra classes, applying for internships, all of that stress, and I practically eliminated all of my hobbies. Not only was I miserable, I was unproductive. And it got worse. Towards the end of the year, my friend got me back into Pokemon by getting me the HGSS game for the DS. Seriously, it was like I was a new person. My relationship with my parents and my boyfriend improved dramatically. I was less stressed about getting a job (and got not one, but two within a few weeks), and got straight A's that semester. The semester after that, in my senior year, I had a full schedule of classes and was working too. The schedule was absolutely gruesome. But since I was playing Pokemon, which I loved, I didn't feel the stresses nearly as bad. My boyfriend learned this the hard way too.. when he went to law school, he gave up all hobbies to study day and night. He didn't do well at all and burnt out. I told him to start back one of his hobbies and once he did, he was more productive, got better grades, and he was a lot less stressed.
Never underestimate the healing power of doing something you love. If you're going to quit something (even Pokemon), do it because you don't love it anymore. But if you really like it, and it brings you happiness, stay with it. It's so hard to find happiness in this world as it is - when you find it, treasure it.