Daaamn, hell of a question😁 I vote for LSD, but drugs are bad. Bad drugs!
Sometimes its legal and enjoyable:)
For a first timer, definitely go with MDMA. As long as it’s legit MDMA there should be no downside.
Also has your gf done mushrooms? If not maybe look into them before LSD.
I found them to be less visually intense but the body buzz was about the same.