Judging from your description, he makes friends easily and has a very large circle of friends. In this case, it should be very easy to enter his circle of friends. In other words, you can easily become friends.

As for how to make her accept you, I dare not make any remarks. My personal opinion is this:

Since he is cheerful, he doesn’t care much about age. Some magazines say that girls should take the initiative; many others say that girls should believe in the charm of reserve. I think the relationship between the two should be handled dialectically. Because you are the one who gets emotional first, so you have to take the initiative appropriately. The key is to grasp this "degree". Once you "fish" him, restrain yourself appropriately. All in all, we must advance and retreat appropriately.

Finally, girls are always emotional, so it is recommended to always remind yourself to calm down and see the situation clearly, so as not to get dizzy.