You are very wise (not to mention kind) to raise these questions now. In fact, your girlfriend is right - establishing comfortable psychedelic equilibrium is a very sensible first objective.
The first order of business with any psychedelic substance is to avoid taking too much, which can
easily cause a bad trip. Some people have a MUCH lower tolerance to psychedelics than others. For example, the people you're with are all taking 2-3 tabs (or grams of mushrooms) and having a great time,
and you can only safely handle 1/4 of that. This is PERFECTLY NORMAL. Tolerance varies RADICALLY from person to person. You (and/or your girlfriend) can avoid ever having a bad trip. Here's how.
Never listen to ANYONE concerning dose. Each person must establish their own tolerance. This is done by trial and error. Start off with 1/4 tab, and if that goes well, next time try 1/2. Follow this procedure for every substance. Mind that 1/2 tab of one substance might well be MUCH stronger than 1/2 of another, so even if you did well with 1/2 of one, you can easily find yourself in over your head if you take 1/2 tab of something else.
Always test each batch of each substance yourself, first.
People disagree with me and I'm fine with that, but never smoke weed when your tripping. That can (easily) cause a bad trip, and it's happened to me repeatedly. Also, mushrooms are high anxiety for a lot of people, so steer clear of those until you are much more experienced.
My advice is to start off with 1/4 tab. With little or no result, a week later try 1/2, which should be plenty.
Never advance more than 1/4 tab at a time after that, and dose only once in a session. I would dose a few times at the same level once comfortable tolerance is reached. Finally, avoid tripping in public. Pick a calm, familiar environment, and a nice sunny day.
Best wishes now and always.
Seen this? :
https://www.youtube.com/watch?v=JTehpkc1PNY
