What an intro post!
Can you elaborate exactly how many friends she's bringing? 3-4 or even more than that? No double dates, I take it either.
It's hard to say, but I doubt it's friendzoning, especially if you're the only guy tagging along, you don't know her friends, and if she remains your main focus, just with them along.
She might want to introduce you to her group, induct you into her life by meeting her friends. Are they her very close friends, do you know?
I'd go, but I'd pay very close attention to the friends. Watch if they routinely make mention of you in regard to her; they're probably gauging how you two work together and the like. Or if they're laughing at you, maybe this is a setup to some ulterior motives as some elaborate ruse. (Don't freak out, I'm just throwing out possibilities based on what you have provided).
More info is good to really grasp the concept. But if you've been talking to her a lot online and know her, and this came up with her approval, I would be nothing but optimistic. Those are all very good signs, and I highly, highly doubt it's anything shifty.
Personally I think it's the reason above, to both indoctrinate you and also possibly as comfort for her. You did admit how awkward and shy it gets between you. Her friends might keep her relaxed and help her and you get the best chance.
All I know for sure is, with women, nothing is ever just because. Her friends are coming for some sort of reason, whether it was her idea or theirs. Time will tell.
Lastly, how old are you exactly? Still school age? Middle, high? Knowing that can help put perspective on the dynamics too. Or are you all adults in, say, college?
Believe me, knowing all that could change a lot of theories.
Love to hear more, and welcome! I'll try and offer insight as best as I can!