I came into this expecting to dislike it, since I watched the anime and it was really mediocre, but to my surprise I really liked the manga, because, in contrast to the anime, it takes the relationship of the main couple (somewhat) seriously, especially in the later chapters.

The story: 6.

The story is nothing to write home about, it's barely even there, but I feel this manga would be worse if they'd tried to force a story in this character-based manga.

The art : 8.

Hajimete no Gal's art is really good for what it is. It isn't the most stunning, but it conveys ideas very well. It's simple at times, but it generally doesn't get boring.

The characters: 9.

This is where this manga really shines, the characters, though pretty much just tropes, get actual character development! Though MC at a first glance seems to be self-insert-otaku-kun, which he kind of is at first, he (and the others) get character development, which makes for a nice story, with changing dynamics, yet still well-established characters. The characters are also actual people that react somewhat like a real human, not in one continuous state of being, but with fluctuating emotions.
None of these characters seem as fake as the type of manga this is would get you to believe.

Enjoyment: 10.

This manga, whilst maybe not the best objectively, is undoubtedly fun enough and worth your time. I really liked it but that's just personal preference, since I like stories based on characters.

Overall: 8.

The Hajimete no Gal manga is most definitely worth your time, it's a pretty good manga, especially if you like manga based almost entirely on characters. It's above average, if what you seek is characters. If you don't like stories centered around characters, this manga is most likely not for you, but I had a lot of fun just binge-reading all the manga's chapters in two days.