It's ok to have feelings, they indicate that you are still alive. And don't swear, people here hate that.
Economics is nice, I intend to study academically this sometime. I wish that you can finish your actual academic studies phase well.
And it's ok to be an old young person, I would dare to say that is necessary. The most powerful and youngest people that I know are in their 60's or even 70's...
Oh yeah. Go for it! You might feel old among the younlings (I definitely did), but it's definitely worth it. And three years fly by so quick, you won't regret it.
Yeah being young at heart is probably a good think. I'm pretty childish, too. :)