I am about to be 15 and my ex about to be boyfriend is 17 and I love him but on feb1 he will be 18 and I don't want him 2 feel bad because I am very mature 4 my age

So what's your question? What difference does it make if he is your ex?

There are no laws governing dating. But since it appears you are planning on breaking up with him I don't understand the purpose of this post.

Ask your parents if it's okay, that will be the right answer.