Honestly, and I'm not a personal trainer here ( I do have fitness instructor certs) but this is my 0.02 cents...(and I don't claim to know everything about any subject!)

You say you know personally the clients you are taking on, but it just takes one injury to have them sue you. My cousin and his wife sued his sister because his sisters friends dog bit their daughter after she harassed it (confusing no?). Family suing family!!!! If families can sue each other your clients can sue you, and then thats the end of your dream.

I know a lot of the posters are coming off harsh, they're (and I) aren't attacking you, but trying to look out for you.

I think you're letting your desire to help people get in the way of common sense (which I know you have, being a military officer!) and good judgement (as far as not taking the internship, and waiting until you're certified). In the long run I'm going to agree with the other ladies here.