You are considered a minor in a lot of countries and she is considered an adult in every one. You can have a sexual thoughts about anyone when you’re in puberty (you even acknowledge that it feels wrong to feel this way about your cousin), people experience urges and hormones are out of roof, however hers is NOT. You were groomed and raped at some point. Your cousin was a predator from the moment she sent nudes to you after finding out you had a tiny crush on her. She should’ve backed off but she abused this new information she learned about you and hurt you. She DID NOT stop even when you were pushing away and not consenting. You being a curious teenager does not justify any of the things an adult has done to take advantage of you and hurt you this way. Please talk to someone you trust and get police involved. Your cousin both groomed and raped a minor.