I feel like you have very little to worry about. You aren't one of those types that gets uncharacteristically hyper or confrontational while on shrooms, are you? Because if any psychedelic drug has had you in a manic state, yelling nonsense in public or jumping on the hoods of police cars.....Well, maybe a solo trip isn't for you. Conversely,if your experience with psychedelic drugs trends towards the typical trips that countless individuals have every day, then I suggest to go for it. Just a couple things you should prepare ahead of time, for those "just in case" things. Tell someone you trust that you plan to do this. If it's a friend who truly cares about you, they'll gladly answer the emergency phone call, should you need to make one. The day before, eat healthy and drink lots of fluids, get plenty of sleep.Just pre-trip double check Spotify or whatever music app you use so that you're confident your tripping mind will successfully locate your favorite playlists when the mood strikes you. As someone who has WAY too many playlists, but only really LOVES a handful of them, it sucks tripping hard and scrolling through all these playlists that just don't make sense while my favorite music seems to be hiding. And if course, as others have mentioned, get comfortable. There's no strict formula here, just be yourself and sit, recline, lay, whatever feels best. I like to solo trip in my bed, but I could imagine a comfy recliner being nice.
I'd also like to bring up a point that even if you are not very experienced, I truly feel that 3gs of dried cubes is nothing to be afraid of. 3gs is like giggling with the friends while thumbing through a cookbook that somehow is written in an alien language. Those days were over 15 years ago now. Back then, while tripping as a group, an eighth was my unspoken limit. And yes, these doses can have quite intense peaks, but I've always found that opening my eyes, checking in my friends and reorienting with my surroundings always worked to bring be back around to the knowledge that I was still here and I was still me.
I took a long break from mushrooms and now I'm using them again. Completely solo this time and pushing the dose quite high. Going over a quarter (7gs) is exactly the kind of mind-fuck I'm looking to achieve. I've gone as high as 10 and it was damn near in the same level of a DMT flash. With these big ones, I never feel the need to do them more than once every 2 or 3 months.
The reason I related those facts was so you'd see that 3gs shouldn't be that scary. Since it seems you're saying it's safe with your meds, then that's one less worry. However, it's never a bad idea to have poison control in speed dial in the rare event that something unexpected, like a food new to your diet, throws a monkey wrench in your metabolism. I think you'll enjoy yourself tripping alone. And shrooms are like the perfect length for an evening trip and still to bed at a decent hour. Also, I wanted to point out that my experience written above shows there was quite a gap between my "less than an eighth/young adult party mushroom days" and my "choke down 10gs, turn off the lights and get ready to soar". I feel like it just sort of revealed itself to me and I knew I was ready to go deeper with shrooms and that I wanted to go there alone and see it all without distractions. Just happened to be my late 30s when this urge struck me and I'm not afraid to admit that my dumbass teenage self would NEVER been prepared to gain anything useful from these big trips.
