I want therapy

I (17m) want to do therapy but I know it can be expensive and take time to actually get a therapist. I don’t know how to tell my parents I want to do therapy again (I did it back when I was 12 for bullying issues at school) because last time they kinda just told me that I have therapy once a week. Should I just wait till I’m 18 and can just do it all by myself or should I tell them and how do I tell them.

Tldr:don’t know if I should tell parents that I want to do therapy.