Jealousy over others pregnancy

So, I am 24 years old and I am married. I’ve always wanted to be a mother and it just seems like it’s never been the right time. I was either in college or not even engaged. Then, it was because I wasn’t married. Now, I am married and the reason is that we don’t have a house. I want to wait so that everything is perfect. I know that it would be easier that way. Recently, my sister in law is pregnant with her second baby. I got jealous the first time she got pregnant. But, it eased my jealousy when I figured out she was having a boy. Now, she’s pregnant with baby number 2 and is having a girl. When I figured this out I was so upset. Not only do I want a baby so bad. But, I want a little girl so badly. Since, both of our husbands come from an all boy family I already felt like having a girl would be slim. I also feel like I am going to have trouble getting pregnant since I have been on birth control since I was in the 7th grade. I know this whole situation may seem silly. But, it all comes down to just wanting a baby and me being jealous. I do not have hatred on my sis in law. But, please tell me some encouraging things and let me know I am not alone in feeling this way.