My sister is ruining my friendships

My sis is 14 going on 15 and I am 13. Almost every time I make a friend, my sister always tries to get in our way when my friend and I hang out. And then my friend talks to her on the phone, hangs out with her, and ect. It's really making me sad. I just recently lost a really great friendship with this girl named Adi because ,my sis and her bonded really well. I feel like im not good enough to keep a friend and them being just my friend. I let her and her friends bond together and I donr inturrupt! It's not fair. I'm loosing all my friends. :-( How can I tell her to stop!

(Sorry if this was badly written!!! Im not in a good writting mood right now! lol, while making this I made like 40 million typos.)

Try talking to your sister about how you feel.
Does she know that its upsetting you? Though you really don't have the right to tell hr who she may and may not be friends with,she needs to understand that you live seperate lives,and that you and her are going to have different friends,no matter what,She needs to respect that you want separate friends,and that your upset how she seems to steal them from you.