I appreciate that external input can be vital but such a fundamental question is something incredibly integral to you and your future so I'd argue it's important that conclusions are utterly your own, Sophie, so you have control over your life. People can help guide you to realisations but you're the one that ultimately achieves them.
Having said that, I hope you don't mind me writing the following and hope it doesn't bias you in any way:
QuoteI sometimes wonder whether I am transgender at all - I like most masculine things and although I'm not particularly manly, I'm not all feminine either.
I don't think liking masculine things or not being feminine necessarily means you're not trans, just as meeting every stereotype in the world doesn't automatically make a person trans either. There's no single correct way to be trans or not-trans/cisgender and no single correct way to express your gender, each person's experience is uniquely valid. After all, there are countless women that adore activities traditionally viewed as masculine and engaging in those things doesn't make their fundamental identity less valid. They remain women because that's what they view themselves as.
For me, masculinity and femininity are just one aspect of gender, the definitions are often indicative of archaic and restrictive stereotypes of what's appropriate for people of a given gender to do in life. They are increasingly being broken down and they are not things with the power to determine the legitimacy of your identity alone.
I'd suggest cautiously and kindly asking yourself about the motivation behind your appreciation for masculine or feminine things if you haven't already and think it would help. For example, why do you engage in them? Is it simply because they make you happy? Is it because it's all you've ever known? Is there an attraction because you're seeking things that make your identity feel more valid? Are you trying to convince yourself something is true? Etc. I found the answers to questions like that incredibly helpful, I apologise if you don't find, or haven't found, them useful.
Above all, good luck with exploring yourself in life and as a member. I hope you find the happy life you deserve as quickly as possible. I can't imagine the pressure you're under right now and wish you the best in finding future options for exploring your gender in a way that brings you helpful answers. You inherently deserve better than to be lost in draining questions.