Wow, that is tough. I play and have coached ice hockey. You are at a difficult age to be switching or making that kind of decision. I feel for you.
Right now, I don't think you should worry about anything except playing well in your tournament, and whatever happens, happens. A lot of things have to happen before this becomes an actual decision to make.
If you do want to look past your next game though (and the coach in me is thinking: just focus on your game, deal with the rest later! haha)....
...here are some questions to think about:
When you say you had planned to transition, do you mean that you'd be living full-time as a boy or did you mean something else?
There is a technical difference in eligibility if you are starting certain hormones (and which ones).
If you're not doing anything medically and just changing your name & presenting as a boy, playing on a girl's team would still out you as trans. Are you prepared to be a boy who plays girl's hockey? Are you prepared to be a trans boy who plays boy's hockey? This affects how people view you, how people expect you to be in lockerrooms, and how teammates/opponents will treat you. Do you live in a state or district that actually has rules about this?
How important is it to you to play competitive hockey of any type? What opportunities for boy's hockey do you have? (sounds like you know you need to look at this further). Have you played goalie against boys your own age often to know how you measure up? Being a goalie can be good and bad. A hardworking kid can often make it as a back-up goalie and teams often need goalies. Plus, goalies can be totally weird and no one cares.

At the same time, it's easier to hide as a hard working weaker player if you can be put on the 4th line. Playing time could be a real challenge.
The jump from pee wees to bantams to midgets/high school hockey are MAJOR ones, and it's the ages which show the most attritition, meaning most boys who play hockey until they are 13/14 then drop out. Girls hockey doesn't have quite the same issue, though it is much more common for talented girls in those ages to be playing up a bracket or two. I 've coached 7th grade girls on par with 11th graders.
It seems like some regions are developing programs and teams to capture the boys who will not be going on to play competitive hockey throughout high school. You may want to investigate and see whether that exists where you live. That may be your best bet.
Now, take a deep breath, and enjoy playing NOW. Hockey is the best sport (as you and I know), and just trust that it'll work out. If you want to pm me, go ahead. I probably have a ton more to say, but don't want to make it all public.