When are you suppose to celebrate an anniversary?

Question

So my boyfriend and I had kind of an argument. We have our one year anniversary coming up. He is saying it’s in a few weeks, at the end of May. I am saying it’s in mid July because that’s when he asked me to be his girlfriend. 
We started dating at the end of May and then made it official when he asked me to be his girlfriend in mid July. So I’m assuming we celebrate in July right?  He says he swore it was “assumed” I was his girlfriend in May when we first started dating because he doesn’t date just to date, he dates to have a long term relationship, which I agree with but you don’t just say your official when you go on a first date because you barely know the person??? Anyway we are confused if we should celebrate in May or July, we are thinking of just doing it in June and saying we are both wrong, lol. Any advice?

Answer

I think July makes more sense to celebrate since that's when it was official! I started seeing my husband about a month or so before we were official. We celebrate our wedding anniversary now but back before we were married we celebrated the official day of being together.

Answer

We go by the day we made it official.

Answer

We celebrated our first date before we got married. I have no clue the actual date he asked me to be his gf.

Answer

I have always celebrated anniversaries based on the date we became “official”. Doesn’t make sense to celebrate when you started dating

Answer

We use our first date because we both wanted serious relationships. I can't even remember when it became official, probably 2 months later but it wasn't really explicit.