I'm also in the UK and it's not necessary now to go to a mental team, all you do is ask your gp to send you to a gender identity clinic (can be anyone in the country you'd like). GPs don't tend to have a lot of experience with trans patients so you may have to be adamant that it is the right procedure. A gender therapist will be qualified enough to know whether you're trans or not and will separate suicidal thoughts from actual trans feelings and will know that gender expression and identity are two different things. Sorry if by mental health team you did mean a gic and I'm just blathering on, a few trans people seem to still think that you have to see a general psychiatrist and then go to a gic and I'd hate for you to waste your time. Btw, I'm 21 and just recently came out to my dad, it's nice to know that not everyone transitions early, good luck 🙂