The longer you put it off, the worse things will get. Seeing a Gender Therapist does not necessarily mean that you'll transition straight away: it's perfectly reasonable for you to see a therapist to help you get your head around how you're feeling right now, so you can then make some informed decisions about what you'll do in a few years' time. You may as well go & see them straight away because they can help you with your current dilemma.
If you're still trying to figure yourself out, why not start with the DSM-V's diagnostic criteria for Gender Dysphoria? A reputable Gender Therapist will be assessing you according to these criteria, so this is a good place to start. In adults, they're looking for the following and you need to have experienced at least two of these for longer than 6 months:
- A marked incongruence between one's experienced/expressed gender and primary and/or secondary sex characteristics
- A strong desire to be rid of one's primary and/or secondary sex characteristics
- A strong desire for the primary and/or secondary sex characteristics of the other gender
- A strong desire to be of the other gender
- A strong desire to be treated as the other gender
- A strong conviction that one has the typical feelings and reactions of the other gender
The words 'persistent and insistent' have been used for many years in diagnosing Gender Dysphoria (particularly in children). The therapist will want to know for how long you've felt this way, and exactly how you've felt during that time. Try to think of examples when you might have experienced something that fits in the list above. So they'll ask about your upbringing: what sort of games you used to play; who you'd imagine yourself as being during role-playing games; what sort of clothing you preferred; what sort of friends you had. They'll then ask you about your most recent history, culminating in the reason why you've felt compelled to go & see them.
They may even ask (inappropriate) questions about your sexuality, I'm afraid. This is partly due to assessing how you relate to your body, and partly due to heteronormativity. Be prepared to be completely honest with them: there are no right or wrong sexual orientations and trans people can be of any sexuality, or none.
You needn't necessarily worry about how you present: a decent Gender Therapist will fully appreciate that we cannot all present as the correct gender in public - especially before hormonal intervention - so if you attend appointments in male mode they should understand & accept this, but it wouldn't hurt for you to explain your reasons for doing this. They may also ask you how you feel when you're wearing clothing that is usually intended for the opposite sex.
Mine also wanted to speak to my family to get a fuller picture of what I was like growing up. My family is unaccepting so this wasn't an option for me. But as you can see from my ticker (below), this didn't stop me.