You don't really "trip" on molly as you do on common psychedelics... you're about to take a drug that floods your brain with serotonin... in other words if you do things right and don't take too much you'll be happier than you've ever been. Be safe, test what you're taking or at least try to research on pillreports, stay hydrated, and you should have a great time. The only way I would could possibly have a bad roll is if I took piperazine(a common adulterant) by accident or something else I wouldn't want in my body.
And about the acting normal thing, I'd forget it. I could act normal on a low dose of mdma but for your first roll I would avoid anyone you really don't want to deal with (i.e. parents, cops, ex's lol)