Quick question, how to know if it's a phase or real? I am afab and I'm leaning towards being transgender but how do I know if it's just a phase or not?
I would suggest you just really look inside yourself to get a good idea of what you really are. If you really deep down believe you are transgender, than it may be so. The other thing I can say is just give it time and wait it out. Don't commit one way or another just yet. It's a major decision and not one that can be taken lightly.
Honestly? You wait. The only way to know for sure that the feelings aren't going away is to prove that they have existed for a significant period of time and haven't gone away. If you have signs that you were trans that appeared when you were younger, that's helpful because it shows you've already been feeling that way for a while. If not, you just wait and see how the feelings progress. You can make certain steps in transition, like binding, changing your wardrobe, and coming out to see if they make you more comfortable. Don't make any permanent changes, like hormones or surgery, until you feel more confident that the feelings aren't going away.