I’m 20M and struggled with this problem for years. The feeling of finding someone attractive or someone being attracted to you and feeling like you can’t continue a conversation is genuinely the most disheartening feeling of all time. The most effective strategy for me has simply just been diving in. Let yourself stutter and if the person has a problem with it, they aren’t the one for you! It definitely sucks the first few times because it feels so stressful, but the best way to manage it is just practice. I started using this strategy and have a wonderful long term relationship. But, I know how scary it is and it definitely took me years to get any sort of confidence, so start slow and I promise it will work eventually. Stay confident!!!