second date nerves or something else?

Hi people.
I am in what I feel is an unusual situation.

I met a girl online (not a dating site) and after chatting there for a week or so we exchanged numbers.
As the months went by we grew very close as friends with her always asking for my advice about men she liked.
In early January she admitted that she liked me a lot and wanted to meet me. I liked her too and we met up three weekends ago for the first time and got on great.
We messaged a lot before that but after this date, i guess we messaged each other 1000 times a day (thanks whatsapp lol) with the occasional call.
We know so much about each other, think alike and click most of the time.
We did try to meet up every weekend since (we both work long hours) but stuff has got in the way.
Anyway; we have plans to meet this Saturday, but I find myself irrationally nervous about it, almost to the point where I feel I might make an excuse to cancel.

Is this a normal feeling to be this nervous? Is it possible that we have waited too long to meet again?

I'm 29 she's 24