Taking a semester off of college to hike the entire 2,175 mile journey on the Appalachian Trail?

Do it during college! This is the best possible time to do it. You can take a semester off from school with minimal disruption to your life - you won't be able to take that much time off once you start working.

Do your research, though. There's a method to hiking the trail. You need to start your practice hikes far in advance - you need to basically go into training. You need to research what supplies are needed. And you need to very carefully research timing - when to start so that you beat the weather. For example, if you start in the south, you'll finish on Mt. Katahdin in Maine - and that part of the trail gets winter weather earlier than some people might expect. You need to beat the weather. You probably want to aim to finish the trek in Maine by late summer/early fall. Certainly no later than early October!

BTW, waive when you hit Harriman State Park in NY. I live near the trail. ;)

if you want to hike the AT, then definitely now's the time. otherwise you'll skip it for now, end up with a house and kids, and not be able to do it until you retire. so either now or between graduation and starting to apply for jobs.

also a good idea to take a semester off school to do it. i met plenty of hikers who were trying to get it done during summer break and they just ran out of time.

missing four whole months of college isn't going to hurt you at all. you'll also get a ton of stories to share with people for the rest of your life, and a lot of people (myself included) come out as better people than when they started. it's an adventure, and who could possibly pass up an adventure???

you don't absolutely have to train before you go, especially if you're busy with work or school. i didn't. there's nothing wrong with having a low average at the start--you'll get stronger as you go and still make the finish in time.

I envy you buddy, go ahead and fullfill your dream as long as you're young.