Friend acting weird

I have a friend of about 1 year. We started out well and seemed to be comfortable with telling me anything. We hang out a lot, at her house, lunch, gm. I thought i did know about her but i did not. She's very secretive. the issue is i tried inviting her out to meet my family. (just sisters, cousin.. not the whole big family), she would either come up with an excuse or ignore. So i tried one last time and invited her out to meet my cousin and sister to a restaurant. she replied with a voice message, she sounded sad and was saying she doesnt know if she wants to go, shes nervous, anxious, her heart is beating fast, she doesnt know anyone, theres a lot of people and we ended up fighting because i 'didnt let her explain herself and got mad at her for refusing my invites'.. bla bla. she refused to tell me whats wrong. i googled it and the only thing i could come up with is social anxiety. Can anyone help?

Try a smaller meet up. You, her and one family member. As someone with anxiety I can say that would be much easier to handle.

Remember that it is HER decision whether she accepts your invite. Please don't pester her to do so. You might just be saddling her with crippling anxiety. Just because you ask her doesn't obligate her to accept. I am sorry if I sound rash but this sounds dangerously close to you obsessing over this and trying to strongarm her into going is tantamount to abuse. If you value the friendship, simply allow her to say "No" and simply advise her that you are available to talk about it later should she want to. Again, don't be pushy, whether it be getting a yes or getting her to open up about a problem she might have. A friend would be accepting even if it is not the answer they want.

You say she refused to tell you what's wrong but she did tell you. You just didn't listen. According to you she said:

'...she doesnt know if she wants to go, shes nervous, anxious, her heart is beating fast, she doesnt know anyone, theres a lot of people.'

You should've accepted that.