I personally think mushrooms are great for a beginner. The duration is short, there are minimal lingering after-effects (eg. you come down to complete baseline before sleep in a more full way than say with LSD, you can sleep sooner after comedown, appetite returns more quickly, less spacey-ness in following days etc), they don't require milligram scales to weigh out, you can get a better idea of how strong they will be as LSD can be unevenly laid or misrepresented in dose and milligram scales can be inaccurate. They also give quite 'full' feeling experiences no matter what the dose, so low doses can make a great introduction to tripping, where LSD or 2c-x trips at lower doses often feel like they're missing something, but full doses of them might be too much for a beginner. Also the fact that they are natural can often give peace of mind to a newbie to drugs, even if it is purely psychological. The experience in itself also gives a good range of the kind of effects to be expected from psychedelics generally, from the more giggly to the more serious.
So yeah mushies would be my recommendation, followed by 4-sub tryptamines like 4-AcO-DMT as they're very very similar, then the longer acting ones like LSD and it's analogues and Mescaline. The only NEVER for a first time would be DOx simply from the duration. Oh and don't bother with 25x-NBOMe, ever. 2c-x drugs would probably come after 4-subs but myself and many people I know bot personally and indirectly have had horrible lingering anxiety/HPPD from using them, IDK why because everyone online loves them, but yeah I don't recommend them to anyone anymore due to that.