Pain in a good way

I recently signed up for a gym in the area because their rates were decent, they had nice classes, and they allowed me to sign up without a contract and the ability to cancel at any time (provided it's 30 days before the next billing cycle so that I don't pay for a month I won't use). I did the free training session yesterday and completely got my butt kicked by this tiny but determined girl. In the end, I had muscles in my legs hurting that I didn't even know existed, which I found to be completely awesome. I decided to sign on for 8 sessions with her, meeting once weekly to supplement the cardio I've been doing (provided she doesn't cripple me to the extent that I'm crippled right now so that I can't run). I have a lot of things I'd like to work on, and obviously I'm not getting it done on my own, so I think this is the best course of action.