Helen,
If there were no practical reasons not to go (and there are plenty), I think the thing that would be holding me back would be a kind of 'social anxiety'.
I'm uncomfortable enough walking into a group of strangers and introducing myself when in male mode. The larger the group, the more uncomfortable I am.
Add in the feminine side, and I'm almost paralyzed. Personally, I would need someone I knew to come with me, to encourage me, support me, and (most importantly) help get me outta there if things start going sideways.
Also, there was the time I was to meet up with a CD group in a local club - and I was the only one who showed up!
Talk about uncomfortable...