Mary Jane is slang for marijuana. Holland is a part of the Netherlands, and Amsterdam (the capital city of the Netherlands) is located in Holland. Amsterdam is famous for its legal pot and 'coffee' shops which sell various baked goods/chocolates infused with marijuana.
By wanting to be Mary Jane Holland, she wants to be high.
I think I could be fine
If I could be Mary Jane Holland tonight
aka I think I could be fine if I could be high tonight.