I've been in love 6 times in my life, and the guy has always said it within the first 2 months of the relationship.
However, as you know, the previous five did NOT
work out, so.... the "timeline" for saying those 3 words, imo, isn't indicative of the success of the relationship whatsoever.
And no, I do not think it matters who says it first.
Now, with my current guy, he just barely beat me to it ... I really was going to say it first. But he also told me that this was by far
the fastest he'd ever said it (2 months in), and that in previous serious relationships, it had taken him a year or more to say it.
I think some people are just much more cautious and or gaurded with their feelings, and he *definitely* is one of them .... but the fact that we'd had a history together going back 18 years gave our relationship a different dynamic.