None of what you said should be holding you back, although it may take some long term planning to get your pre-reqs done, and to get some observation hours.
I'll be 40 soon, and I'm looking to change from being an architect to a physical therapist. I'm planning to apply this Fall for school in 2011 (still figuring out where to apply).
I don't know where you live, but the community colleges here offer classes mornings, afternoons, evenings and weekends.
It seems most hospitals provide volunteer/observation hours weekdays during the day but there are exceptions. Outpatient clinics, especially independently run, should have some evening and weekend availability.
I'm assuming it will take at least a year to get your pre-reqs done. If you start 3-4 hours a week now, you'll have plenty before you apply. I just started mine in March, and plan to have around 200 hours by the Fall. Even if you're planning to submit your application this Fall, you can get a reasonable amount of hours.
Most schools do not require 100s or 1000s of hours like some applicants on here have. They mostly want to see that you have a 'taste' of the profession so you know what you're getting into. For most schools 40-60 hours is sufficient. For some even less. Some even don't have a minimum stated. It should be easy to find out for the 2 schools you want to apply to (check their websites).
Admission to DPT programs is competitive, but I don't think nearly as much so as it is portrayed. There are plenty of statistics you can look at, especially at
www.apta.org and
www.ptcas.org
and the websites of the schools you'll apply to.
Most of the top programs state that the average for accepted students is GPA 3.3-3.6 and GRE's around 1150. And those are the top programs. Don't get me wrong, those are good numbers, but not everyone has a 4.0 or perfect GRE's. Your GPA isn't quite in that range, but it's not bad. And remember, if the average GPA is 3.3 or 3.4 or whatever, that means roughly half the students had GPA's that are lower. Most schools require a minimum GPA OF 3.0 which you have. But even some schools, including top rated USC, consider applicants with less than a 3.0.
And acceptance rates are not astronomically low. Top notch programs like Northwestern and USC, say they 'enroll' 33% of qualified students. So, they likely accepted much more than that. NYU says 60% of students are admitted.
www.gre.org has practice exams so you can get an idea of what your scores will look like. And it'll help you see if you want to put some effort into studying/preparation before you take the actual exam.
I think your background in law enforcement will be very interesting to a lot of application committees. You have a decent foundation to work with. If you plan well from here on out regarding your pre-reqs and observation hours, I think your chances are very good.
Good luck!