I dunno if I'd even call 4-MMC an empathogen - never tried it but from what I hear entactogen probably applies better. The two terms emerged as interchangeable for MDA and MDMA, but I think we have enough similar compounds to diverge the labels. A lot of Meph users report that it lacks the empathogenic qualities of MDMA while still enhancing touch and producing physical euphoria.
At any rate, as for a first trip, two things I would say:
1. On the question of bad trips... They're always a possibility, but worrying about them is one of the most common ways to cause them. So long as you have a good set and setting - generally positive mindset, no huge crisis in your life right now, especially one you've been avoiding dealing with, anyone else who is present is a good friend you are comfortable around, no unexpected interruptions by parents or other authority figures, etc. - you will *probably* have a good time. That said, psychedelics are very effective at digging up unconscious material. This can manifest as anything from the most profoundly wonderful experiences imaginable, custom tailored to details even you couldn't explain about yourself but relate to deeply... Or it can be quite unpleasant. The most common 'bad trip' experiences fall into one of a few categories: negative thought loops, where your mind gets 'stuck' on something unpleasant and you have trouble changing topics (distractions like music, conversation, tv/movies, etc. can help, with experience these become much easier to break out of at will but the first time it happens can catch you off guard); scary visuals, which you just have to remind yourself are not real and stop paying attention to (it's rare to see spiders or psycho clowns or shit like that, usually it's more abstract patterns and symbols but it's not unheard of); or really negative bodyload which can make you think you are sick or even dying. Fear of death can also be a natural reaction to what's called "ego death" - this is a fear many never get over, but most find after experiencing it that they are very grateful for the experience, as it can teach you a lot and be very valuable once you get past the fear part. As for bad bodyload, the two best solutions are 1) avoiding psychedelics with bodyload issues or 2) when using those with bodyload issues, remind yourself of this when you feel like shit. Personally I mostly choose option 1, but I'm a wuss when it comes to nausea and bodyload.
2. Whew, onto the second thing - suggestions for a psychedelic to choose. If you want an easier entry into the world of psychedelics without as much a risk of a bad experience, most people find the phenethylamines gentler in general. The most common of these are mescaline and the 2Cs - 2C-I and 2C-E being the most common of those. They are less common than mushrooms and even acid in many areas, though, so I don't know if you'd be able to find them so easily. Mushrooms are probably the most common psychedelic in the States and therefore many peoples' first and even only psych, but they are also among the most intense. Before I started having nausea problems with them I loved just about every mushroom trip I had, but my most difficult trips aside from the peaks of a couple very high dose LSD experiences were pretty much all mushroom trips. LSD is harder to find these days than it used to be, and it lasts a long ass time (a good 10-12 hours at least unless you take a very small dose), but it's many peoples' favorite: it can be 'intense' like mushrooms but typically leaves you a bit more in control. Mushrooms can almost seem to take over your brain so they can show you what they want to while you follow along in a dreamy haze; LSD is more like opening doors and allowing your fairly clear-headed conscious mind to explore some pretty weird places it normally doesn't get to see. A good friend likes to describe LSD as "like having superpowers" in that he feels much more in control of how the effects manifest. LSD can get quite overwhelming at times, don't get me wrong, but it tends to leave you with greater control and a clearer mental state than mushrooms.
If you are excited to explore the psychedelic experience while remaining as open-minded as you can about what to expect (whatever you expect will probably be wrong, but don't worry - the real thing will make your expectations seem trivial and boring by comparison!), with a good set and setting prepared for yourself, I think any out of mushrooms, LSD, mescaline or 2C-E would be great and similar alternatives like LSAs or 2C-I would be fine, too.