4 months is nothing mate, i'm actually doing maps since 2005 and i'm still not that good, keep working on your stuff, aim to make some small pieces of maps instead of trying to make a complete one, don't be ashamed to copy and to take inspiration from valve's maps at this point, but be creative with what you are copying and try to hide it as much as you can.
The thing is, try to break the whole mapping skillset into small pieces, like detailling, level design, brushwork, texturing, optimisation and so on, and try to master one of them, and be good enough at it, then work on something else and so on until you get good enough to release a map. Imo you should try to understand at first how to make great brushwork, look at valve's maps and take inspiration from there, and try to copy a building to understand how it's made, and once you get the thing, try to extend it as much as you can.
Also, art and level design is a completly different job, most of the people who are working in the game industry are either level designer or artist, they don't do both, so be aware of that and try to focus on one thing at first.
Anyway there's no trully defined steps for someone who want to learn, the only important thing is that you should always have fun with what you are making, and then you'll make huge improvements for sure.
Oh also don't look at other's work, some people here are really good and have been making maps for years now, don't feel the need to compare them to you the only important thing is that you are working on your own stuff, your level doesn't matter.