Dia Dhuit-

I will be getting married on June 3, 2000. I have to figure out the party favours and I have chosen a silver frame with the map of Éire in it. Below I want to put the date in Irish and needed to know the right spelling.

Which (if any) are correct?

3 Meitheamh 2000

or

3 mí an Mheithimh 2000

If you could help me that would be great. Thank you.

The first one is better, though both are correct. It's the standard way of writing dates.