My daughter was only 11 at the time (now 13) she has issues with eating,withdrawing and other stuff that I can't say here.
The staff are brilliant I can't fault them at all, First session I think we spoke for about 2 hours accompanied by 1 of her teachers too. They ask a load of questions and yourself too and then will decide how often you should attend,My daughter attended every month but wouldn't talk to them much as she is so shy so they discharged her after 6 months.
She still haves problems now, They did say if I am still worried is to contact them again, If you're still at school they will probably have a meeting with your year tutor too to see if you're getting the help that you need (well they did with my daughter)
Good luck