One thing I just want to gently remind you about is that the community here is very diverse and absolutely includes transmasculine people with vaginas. So, when we have conversations like this, it's important to keep in mind that they won't ever be conversations where the people you're having them about won't also be here reading them or sometimes even answering the questions. Just be sure and be as sensitive as you can. <3 I also want to give you props for asking -- I really appreciate you wanting to check in about this and caring.
I think this is a tricky thing to answer without knowing what you know about a few basic things to start.
For example, did you know that genitals are not even actually dimorphic in the first place? In other words, we often talk about them and reproductive systems as two groups or ways, particularly when we're giving people the most basic information, but they are actually much, much more diverse than that. Reproductive systems as a whole are more complex than just being one way or another, with a range of variations, and external genitalia are waaaaaaaaaaay more diverse than that. It's actually pretty fair to say that external genitals exist on a spectrum, and there are points on a spectrum where you would find it very difficult to look and say whether someone even *has* a penis or a vulva, and you'd have to ask them. (This is also all tricky for some intersex people: some intersex people don't fit standard M or F chromosome or genital assignments and don't want to be made to fit them or to have to pick from them.)
Which leads me to my next point: which genitals we have when it comes to what*gender* they are is totally up to us. The idea that men have penises and women have vulvas is, itself, for sure a transphobic concept, because it literally excludes and discriminates against transpeople. It says that genitals say what your gender is, not you, and if you say you are a given gender and don't have the genitals that "match" either you or your genitals are "wrong." That's textbook transphobia.
I say all that instead of just answering your question with a simple yes or no because I don't know how much you even know about even those two very basic starting places for all of this. If all of that is news to you, then it may well be that your attitudes are transphobic, but those attitudes are probably entirely inherited and learned rather than really your own, you know?
Let's not get too deep just yet -- I'm going to take a puse there for now and see where you're at. How do you feel about that?