It sounds like you're in a bit of a dilemma. You've always been a humanities student, but you're starting to develop an interest in computer science and mathematics. However, you're worried that you won't be able to keep up with your peers in these subjects, and you're not sure if you'll enjoy them as much as humanities subjects.
It's important to remember that you're still young, and your interests can change over time. It's also important to follow your passion, even if it's not what you've always planned to do. If you're really interested in computer science and mathematics, then you should go for it! You may be surprised at how well you do.
Of course, it's also important to be realistic about your abilities. If you're struggling with mathematics and sciences, then you may need to put in some extra work to catch up. There are plenty of resources available to help you, such as online tutorials, Khan Academy, and tutoring.
Ultimately, the decision of what to study is up to you. But if you're not sure what to do, I would recommend talking to your teachers, parents, and friends. They can offer you some guidance and support.
Here are some things to consider when making your decision:
What are your interests?
What are your strengths and weaknesses?
What are your career goals?
What are your financial resources?
What are your family's expectations?
Once you've considered all of these factors, you should be able to make a decision that's right for you.