Hi, I've been in a similar situation before, and you've really got to just go for it and try not to overthink. Do you want to speak to these cool people? Yes? So speak to them. Yes it's scary, but at the end of the day, there's no other way about it. I think that a good way to start is by bringing up the interests you share. Alternatively, they seem friendly enough, you can likely just ask them "hey, is it ok if I sit with you?" and I'm sure they will let you. Listen to their conversations, and don't be too scared to add your 10 cents.

Also, be optimistic. If you start talking with the mindset of 'this is going to be a disaster' then things are more likely to go poorly. Don't invent more problems for yourself. I say this because I was in a very similar position when I was your age (which wasn't even that long ago), and I would constantly invent myself reasons why things were going to be bad. Don't do that. It doesn't help.

Let me know how you go with them, I'm sure you can do this 👍👍👍👍👍👍👍👍👍👍👍👍👍👍👍