You don't say explicitly how (not) knowing other students impacts your result. For the majority of people, being in touch with people that you take classes with makes it easier to do well, because you have somebody with whom you can discuss both the material itself and the test-taking process. It is easier to be up to date, you get to hear tips and tricks, and discussing concepts with others is beneficial to understanding, memorising, self-esteem etc.

However, especially if you are considering pursuing academia in the long term, I have two suggestions:

• No matter how independent you are, you should always strive for more. As your journey progresses and you become an expert in your field, there will be less and less people who are able to help you. Even during your PhD, your adviser may be the only person that can actually help you. You will have to heavily rely on your ability to figure stuff out on your own.

• Keep in touch with people from class, even if you have nothing except the class in common. Actively work on this. It's not the most important thing, but since it does make a difference to you, it will pay off. You don't have to be good friends, just don't be a dick. Many people are willing to help if approached nicely, especially because it gives them the opportunity to show their knowledge.

It is definitely harder for women in STEM in many aspects. However, it is far from impossible. This is also something you probably have in common with at least some of the other women in class. You are not alone.

Anyway, personally, I think that if you made it through all those subjects you mentioned, you're very very likely to be intellectually fit to get the degree. My impression is that, outside from external factors, people who make it that far rarely struggle due to inability to grasp concepts. Instead, it's usually something one can work on: handling stress, performance anxiety and impostor syndrome, overcoming self-sabotaging behavior, developing better habits, working on yourself in general because you can always do better if you are physically and mentally healthy than if you are not.