After my first ever "thing" I wrote (see story here: https://devrant.com/rants/2132057/...) fast forward 7 years to my first project when I /* thought I */ knew what I was doing and didn't write just for myself.
Preset:
I worked in a very small company distributing various materials for medical research, many of them bought from manufacturers and then relabelled as if we had produced it. One part of that was to indicate a production batch / lot number. Before I started there, they would just invent a random number on the spot and use that on the new label and somewhere write it down to document that, I at least used an Excel sheet to have numbers prepared and document it on the same line (still crappy but more than nothing). After some time my boss got the idea to have all of that documented in MS Access (because that was the only database he knew). I had just started with HTML, PHP and MySQL in apprentice school around the same time, so I proposed writing an appropriate solution using those and got permission.
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I started coding and learnt so much that I didn't need to pay attention at school anymore as I was years ahead of the curriculum (the others were struggling with If-statements and the likes).
When I was done with Version 1.0 of my web application, it was of course still crude as hell. I used html forms to save input (like editor.php -> submit to save.php, do save -> redirect to editor.php), but it did what had not been done before: keeping it all together and force people to do it properly. 2 years later I wrote a version 2, adding features that showed to be useful and with improved structure, as my last project before leaving, and as far as I know, they are still using it, which is at this point 2 years after I've left.
Looking back I would do it differently, but for what I knew back then it was not bad at all.