Test the waters a few times first, see what the reaction is, ask a few times even if u dont go, get them used to idea & if ur still with the same guy then think they'd probably say its ok
How many friends? How old are these friends? Do I know these friends personally? Do I know your boyfriend well? How long have you been dating? As you can see.. I'm a parent and these are the questions I would ask. As long as the answers are honest and 'okay' I would certainly allow it.
Of course, at any age.
if my parents didnt let me I would really have a problem :P