Alas, another "what-are-my-chances thread". PLEASE PLEASE give me some advice, I'm quit panicked...
Don't panic. There are MUCH worse things than not going to med school. Academic credentials aside, if there's ANYTHING you want to do as much as medicine, it's probably smarter to do the other thing. And if you decide to go for it, great.
What's the difference between DO and allo?
DO is what you are more likely to get into, starting from a 2.75. DOs and MDs get arguably the same education and training. DO schools are arguably more forgiving/accepting of nontrads. (DOs also study OMT/OMM, which is the basis of chiropractic, which is why DO is arguably controversial.) DOs have arguably fewer practice opportunities. Some states, and some countries, don't recognize DO. There are fewer DO schools in the US.
All those "arguably"s should be your clue that DO vs. MD is arguably the #1 running SDN argument.
Somebody's going to mention the Caribbean, which is where you can become the equivalent of a foreign medical graduate if you have money or credit.
I'm 41 and applying this year. If you couldn't literally be the grandparent of one of the 18yo kids applying this year, then shut up about old.
a non-traditional student (in the sense that I'm a first generation college graduate)
This is very good. Some schools will view you as underrepresented and give you more wiggle room with numbers.
volunteering in hospital (oncology/post-op); have research experience;
This is also very good. Keep doing both - build up multiple years of involvement. Look for other community activities that you enjoy and can describe with a passion. Try to get your name on a paper, and make sure you can describe what you worked on.
haven't taken the MCAT, yet;
Now might be the time, meaning this winter or spring. You want to have completed bio/chem/ochem/physics, which I assume you have, fairly close to test time, so that you don't have to review. With your GPA, you probably need a prep course.
Your MCAT score is going to be a very important companion number to your GPA. It can't fix your GPA. But a strong MCAT will give you credibility. Strong in my mind is over 30, preferably over 35.
I'm about to graduate from a public university (BA-biochemistry/chemistry); low gpa (2.75);
OK, so 2.75 is low. Schools also look at your science GPA, so you need to know what that is as well. Note for the record that undergrad GPA is separate from graduate GPA, so you arguably can't fix your GPA by going to grad school.
You might be able to get into a Caribbean school with sub-3.0. You might be able to get into DO with sub-3.0. But the frank question is whether you are ready for the rigors of med school, where your classmates got a whole lot of A's to your B's and C's.
You can take more classes to improve your GPA. Note that I said improve, not fix. If you do the math, you'll see that you will need to spend years getting above a 3.0 or 3.2, and a 3.5 is probably the upper limit. It's also a mistake to plan on getting a 4.0 "from now on." You might find, like I have, that you can't just turn a switch and start getting a 4.0: it doesn't mean you're not smart, but it might mean that you have to truly suffer while your classmates don't, or that you need to work with a tutor/coach/shrink. You might not have a 4.0 in you. Maybe you do.
With GPA damage that can't be undone (which you and I both have), the only real saving grace is to show a strong, consistent, upward trend. That is ALWAYS the story when a low GPA candidate gets in.
If that BA is the teaching option instead of the grad-school-prep BS option, then you may need to take the harder versions of ochem and bio than you took.
Situation: I'm about to graduate from a public university (BA-biochemistry/chemistry); low gpa (2.75); What can I do to get into med school? How do post bac programs help me get into m-school?
If you've already taken the med school prereqs (genchem, ochem, bio, physics), then you can't take a traditional premed postbac.
You can always find a school that will let you take more classes, to show GPA improvement. You can consider getting a second bachelors.
You can think about an SMP (special masters program), which puts you through the first year of med school to demonstrate that you're a worthy applicant. This is the do-or-die, last-ditch option for allo, because everybody in an SMP has just as much to prove, and if you don't win against your classmates, you might lose everything.
In your shoes, I would push to get ready for the MCAT, and based on that, see where I'm at. If I'm happy to do DO, and my MCAT score is 30ish, I'd apply DO. Otherwise, I'd graduate and take time off. I'd almost certainly do a Peace Corps gig, gain a strong second language, and then see where I'm at when I return. If I still want to go for medicine, I'd probably start a second bachelors and put a strong application together.
My $.02. Best of luck to you, and keep us posted.