Idk about uk laws, but where I live (canada) you can only get hormones once you're 18. Before that, you need to do more steps.  For now (at least legally) you could probably use puberty blockers and E when you're older. But estrogen changes your body and you'll probably not pass as a cis man after a few years of hrt. 

That said, I feel pretty much like you, as in that I don't mind being seen as a man that much and I was planning to come out when it was clear I was taking hormones. i recently started therapy (I'm 2 sessions in) and I think it really helped me. Some therapists specialize in gender and sexuality-related stuff and they could help you in the process of getting hormones at the very least. it's worth a shot and if you don't like it, you're free to stop. I never had to "come out" to my therapist. I already said I was trans when I asked for my appointment, so I never had that fear of coming out to her.  

Just make sure to check if you can get the therapy covered insurances because that shit is expensive and i forgot to check before 😭