We are still early teens but we know our limits (eg: no sex until after marriage, and etc.) He's also afraid of pressuring me and makes sure he doesn't. So is it bad to let him touch my breast or no?

I guess it's not wrong, just as long as you are absolutely sure you are clear about and true to your boundaries and you don't do it in public.

Being clear about your boundaries and being sure of it is important. You don't want to do something that you are essentially against because that could do some moral damage, which can get really ugly. It can mess up your self-esteem, interfere with relationships of all kinds, and the damage goes on and on. You may not think that it would, but it could seriously impact you deeply, so be sure that you are strict about your limits as well so then nothing goes overboard.

And you don't want to do that in public because people just don't want to see that, okay. That is definitely something that should be kept private.