Wedding!!

We have been engaged for about 3 years and finally 2 kids later have decided to get married next August. I am pregnant but due in April so that’s not an issue for me. My issue is that I have no one I want to stand up with me on my day, except my sister. My fiancé has his three brothers standing up with him and I thought about using my future sister in laws but I just really don’t want to anymore because I’m not close enough with them. I don’t have any friends that I’m in contact enough with to want them up there. I guess my question is; would it be weird to just have my sister stand with me and fiancé having his three brothers stand with him? Or should I try and even it out?