We can't know her intentions: really going for a meetup, just grabbing some attention in a proactive manner, or stringing along an orbiter. Maybe you already found out by now!?
It might be all three also. That's the beauty of that power game, she basically can't lose because she can always change her mind later.
It's not the age gap, I think. Women showing interest and then having opinions about an age gap is usually a sh!t test.
What I think is the simplest explanation is this: she might have realized afterward that she was too proactive for 'standard' male/female interaction, so she's backpedaling a bit (by grabbing something random like your age gap) to see if you are willing to put in some effort just like her (by passing her sh!t test, of course) and balancing this out and be on a level playing field again. She might think that she signaled that she is an easy lay.
If you haven't by now, you might want to tease her with this. Tell her jokingly that she acted like a horny man. Flip that script and tease. Tell her that you're not an easy lay, and that she has to take you out to a fancy expensive restaurant and that you expect her to ask you to marry her within one year. That you want flowers. That she better be handy, because the plumbing in your new house has to be done.
I'm just making stuff up here, of course, but you get the gist. At least, try to refuse the urge to become the proactive man in this case... you're failing her sh!t test the moment you start proposing plans for a date. The times that women were so proactive with me, I thought I was already in, that probably was noticeable in my communication, and most of them lost interest.