Should I have sex with just a condom?

So my boyfriend and I are thinking about having sex very soon. We are both ready and I’m going to the doctor to be put on birth control tomorrow. With that being said, it’s very hard for us to find time to be alone and we have a night where we can have sex. It’d be my first time. The bad part is that I will probably not be on birth control at the time. If I’m in my fertile window, but we use a condom, would I be alright? We really want to have sex, but I don’t want to get pregnant 😂