I agree with everyone else. I would do it, what do you have to lose? If you only learn ‘what not to do’ it will still be quite valuable. There are other things besides taking a good photograph to running a successful photography business – such as business skills, confidence, the way the tog deals and reacts with clients etc. It is all important to learn.
I’m in the same boat with you, just trying to start out, build a portfolio, shooting for free etc. A few months back, I had an awful session with my friend, I had no clue how to direct or pose her at all – other than say ‘smile’! I had great help from a thread on here about it and found a few videos on you tube too. There is one particular woman who I have watched a lot of her stuff simply because I really like the way she interacts with her clients and it has been really helpful to me. I’m actually not too interested in her work, as I’m learning other things from watching her videos, how to pose, get the client to relax, direct etc.
So my point is really you may well learn other things from working with this tog. She must be doing something right and/or have a good business sense, as she is more established. Good luck.