I get that, and you have to make your own choices about that, but estrogen can be supportive without necessarily forcing you to socially transition, there are many people who take estrogen but are in the closet still. Depending on how you dress, speak, and interact, you probably can pass as a male for longer than you think.
It depends on a lot of things how soon you will start to appear as a woman to people. If you have short hair and not a lot of body fat I think it would be easier, since it’s hard to grow breasts without much fat. If you are heavier you are more likely get more breast growth and it might be harder to hide that without a binder, but even that can be managed. If you have facial hair or heavy beard shadow, that heavily skews perception towards male.
You might look back and think waiting for security in your life before starting estrogen was a mistake, especially if estrogen is necessary for your brain to work well like it is for me. Even without that reason, your body will undergo further androgenization, which for me increased significantly in my 20s.
Just worth thinking it through. If you have to keep it secret from family or people you live with, you could always do DIY route to avoid the paper trail that visiting a doctor causes.
Just don’t underestimate how important estrogen is.