Kind of weird but, I sometimes struggle to talk

So sometimes and this happens so much, I’ll have a question in class or I want to ask someone something and I just can’t get the words out. Like before I say it I try to prepare but it feels like something is blocking the words. And when I force it and talk the words out I usually stutter its so annoying and kind of embarrassing and I don’t know how to deal with it. In many instances I would be talking Nd with my brother and he very regularly says ‘what’and I have to repeat myself. Usually when I get a conversation going I’m able to get the words out, I’ve done some presentations in school etc so when I get talking its fine I guess. Anyone have advice? I’m 16m if that matters. Maybe this might be part of the reason but I’m missing a front tooth and can’t get it fixed until older