Ya I wouldn't eat more than a half eighth your first time and definitely do it somewhere that you feel comfortable and around people you are comfortable with.
Some tips you need to know:
1. There is no such thing as a bad trip. You only have a bad trip when you tell yourself "OMG I'm having a bad trip". So just stay positive and happy and you'll have a blast.
2. Depending on the strain, some mushrooms can be more than twice as strong as others.
3. Never eat picked ones if you can help it, they fuckin grow in shit and if they pick the wrong kind you have no idea what you are eating. You can tell homegrown because they have thick (usually white) stems instead of tiny little stems (except for the pinners)
4. Pinners are the shrooms that have a cap that is just about to open. These are the strongest by weight. So if you eat a half-e of pinners or a half-e that is 2 big mushrooms, the pinners are gonna get you WAY more fucked up.
5. Bigger isn't better: when the shrooms get past pinner size they don't make much more psylocibin they just grow more plant matter.
6. Keep some weed on hand (if you smoke which I know you do). It'll calm you down and also make you trip a little higher. Keep in mind you won't really feel "high" from it just a little calmer.
That's all I can think of right now. Either way have a fun time!