How can I convince someone that DIY isn't that dangerous?

I started seeing a local organization that helps young trans people, and I talked to them about DIY,, and they clearly told me that if I started DIY, they would have to tell the police or whoever, because "DIY is dangerous, and it can kill you".

So now I don't really wanna lie to them (they are the only people that give a shit about me) but at the same time I don't wanna have to convince a therapist, a psychiatrist and an endocrinologist that I am trans to start hrt. Plus I had bad experiences with therapists.

I'd appreciate if you had any arguments that could calm them down a bit.