You have to think positively. Having the stutter definitely is something that's difficult to deal with but having a negative mindset doesn't help at all. If you keep telling yourself you'll never be in a relationship, then you're not gonna be assertive enough to be in one. Telling yourself no girl is interested in you is also false thinking. You never know what someone will like. A girl may not care too much about the stutter. If a girl likes you enough then she'll probably be able to look past it. You have to relax and not overthink. You should definitely start working on yourself though. Whether it's going out and socializing more, working out, setting a goal or whatever. Just try to better yourself whether mentally or physically and just go for progress. Start dming girls or flirting with girls in real life. The worst thing would be them laughing and saying no. Literally. You're not going to die. Your probably not gonna see that girl again. She won't go tell everyone how she rejected you. In the end you get experience and results and more confidence. Good luck