This post is directed at the OP, but applies to traditional undergrads as well. Anyway,
I'm assuming you're an EMT-B already, since that is usually a mandatory pre-requisite to becoming a paramedic (though this might be different in other states). Great, you got a head start on your med school hopeful peers, you don't really know too much as an EMT-B so you still have a healthy appreciation that you don't know very much about medicine. Believe it or not this is a wonderful place to be. I strongly advise you to stop right there (at EMT-B) and devote yourself entirely to becoming a physician.
Here's why:
EMS is a bit of a trap, you can get all caught up in it, because you are enjoying what you are doing, helping others, taking care of emergencies, etc. It's a good high when things go really right. Then you meet a paramedic, and think to yourself: boy can this guy take care of business, I'd really love to be able to do all that great stuff too! But there is really not that much to being a paramedic. Unfortunately nobody really tells you this. IN your world, all these new skills are exciting and impressive, So then things start to take a turn in your life. Let me tell you a little about what I mean:
Paramedics are funny people, they are experts in a very, very, narrow slice of medicine. In fact, when it comes down to the business of prehospital emergency care, nobody does it like a medic. WOW, I think I want to do this medic thing, I'm going to go for it, atleast for now, until I go to med school next year. BUT, you can easily get all caught up in the ALS pre-hospital care scene. Because you are doing life saving interventions you may feel like you fast forwarded yourself to "doctor" or at least the preconceived notion you had of doctors before you ever got involved in medicine. So anyway, there you'll be doing all these great skills, and soon you'll start to think that gee-whiz look at all the great things that I can do as a medic (ha! nurses my ass, they can't do this stuff!). Heck, all that other stuff in medicine really is not as important as this stuff I'm doing right now (IVs, intubation and pacing oh my!), and that's when you start to make a very big mistake. All of a sudden you really stop caring about all the other things that medicine has to offer, so you stop learning about anything that doesn't have anything to do with the "important stuff". Now depending on how long this lasts you can piss away 4,5,6 years doing EMS work and be totally satisfied. But then something happens, it can be some job that went bad on you or you come across something you've never been prepared to deal with, or any other number of things that cause you to become reflective about yourself as a professional. So then you start to read again and you once again rediscover that there is a whole world of medical knowledge out there you weren't aware of as a medic. So now you're studying again and learning about the things you didn't know, but you are never able to do it in any coherent way. The sheer volume of the material is intimidating and you have no real way of knowing if you are making any progress. Plus you are surrounded by your peers, fellow paramedic professionals who tell you things like who the heck cares about temporal arteritis, that's not important and what the heck is so important about this pancreatic psuedocyst you speak of??? So now you start to get frustrated, and you look around at the people around you who are very content with being medics and knowing what medics know, and incorrectly equating their skill proficiency with medical knowledge. But not you. You start to remember that you wanted to be a doctor, and you look back and say, how the **** did I get here, this isn't what I wanted for myself professionally or personally. This whole medic thing was supposed to be a stepping stone to becoming a physician. You become, really frustrated, pissed off, burnt out and then to add insult to injury you start to realize that you are wildly underpaid for the work you are doing. Nurses don't have to put up with 1/2 the crap that I do and they get paid 3 times as much, plus I know a hell of alot more! That's the last straw, F-this you say, I'm going back to school. Only now you are well into your mid- late 20's, (in your case, mid-late 30's) maybe you got a mortgage, a big monthly car payment, who knows maybe a wife and kids in private school, your Golden Opportunity to become a physician is now well past you. You now must suffer in new and interesting ways to get to where you wanted to be in the first place. So sacrifices and painful choices are made and finally 7-8 years later you are back on track for the MD, older, a little more worn out, less enthusiastic, but hopefully a little wiser. Maybe.
So the question is, are you absolutely, positively sure that being a medic is what you want? Think long and hard about this, this is your life afterall. That being said, you gotta do what you gotta do, if you are supporting your whole family or you are on your own out there I can understand. But think about this seriously think about this. This is a long post, but I did not make all of this stuff up, I speak to you from my experience. There are alot of other things I can go into, all sorts of crazy stuff that you'll be banging your head against, but I think I'd be writing for days and days. Anyway best of luck, you can always drop me a PM if you have any specific questions.