Do it early for you get too involved and stuck like me! I've got two associates degrees, and 80 credit hours towards a Bachelors in Mechanical Engineering and I absolutely hate it!

I work on cars for a living, in fact I have my Master Certification but its just a job, don't love it, but don't hate it. The problem is, is that Im not passionate about it any more and that it isn't something I want to spend the rest of my life doing.

Starting in the fall for a Bachelors degree in Environmental science and hopefully get a job with the parks department or even a Game warden.
Im $40k in the hole and now changing majors.... wish I would have listened to my heart instead of my father and changed years ago.