Tripping alone has distinct advantages over tripping with others, but also has disadvantages.
The main advantage I see whilst tripping alone is that it allows you more freedom to 'explore'. Basically meaning, more freedom to do and act as you wish.
I mean, sometimes, even when you are with best friends, you can sometimes feel slightly restricted whilst tripping. This is my opinion anyway!
Tripping alone allows me to explore stuff about myself and my life in a much deeper way.
When I trip alone, it's always a lot more 'ritualistic', and I feel i'm using said plant/chemical as a powerful tool rather than for pure recreation.
I plan it all maticulously days in advance, think about what i'd like to try and 'explore', what set and setting is appropriate.
It's always a deeply personal affair.
But it does have it's disadvantages.
Feelings of 'loneliness' or 'isolation' can pop up on some psychedelics, and at these times it's always good if you have people you trust around to counter-act these feelings if they arise.
Being alone, those feelings can sometimes get out of hand.
Sometimes if you are tripping very hard you need people around to ground you again, though like mentioned previously, once you are experienced and used to the effects of psychedelics, this becomes much much easier, and none of these neagtive reactions should turn into any significant problems........But then again, you never really know for sure!
So, my opinion is that you probably shouldn't trip alone the first times until you have gained some experience.
Though saying this, my first ever trip was with morning glory seeds, and I loved it. Though the second time was a very dark trip.
And also , my first true mushroom experience (4 or 5 grams) was by myself, which was quite foolish because I was naive and thought it was just going to be a shorter, less intense version of an acid trip! That trip wasn't all bad, had some really great moments, but I wish i'd taken them around people the first time bcos although it was similar to acid, it had a lot of different effects too!