The problem is it is difficult to tell 100% if you are having permanent loss with short term qualitative measurements. Your hair will sometimes be thicker or thinner throughout your life but it does not mean it is permanently receding.
MtF hormones have been proven to prevent and reverse hair loss so if you are truly considering being a trans woman, this will be one of the most effective strategies.
You can also look into Minoxidil topically, dermarolling+Minoxidil, oral Minoxidil, LLLT (combined with the prior mentions), topical anti-androgens (RU and CB).