>>102536Im the guy you replied to
Ideally you want to only be friends for a couple months before asking them out, not years. Then you are mentally "the guy who i get along with" and not "my close friend of 5 years". For some it can even be surprising if you ask them out after a while.
If youve been getting along for so long though, just ask her out. For the first date choose something where either of you can make an excuse and leave it is clear it wont work. So something like a cafe or park walk or something rather than a restaurant dinner date or cinema