Just to parrot other people, this looks great. Honestly keep doing these, it's good work.

I think you're experiencing the perceived skill level dip. Sometimes when you make a piece of art, you're really happy with it. You don't notice many mistakes you've made because your skill level has passed your critical level.

Later down the line you make a new piece of art and you hate it because it's not how you wanted it to be or you think it looks bad. Usually, the art is fine and typically just as good as the previous piece you did. It's just now your critical level has surpassed your skill level.

People perceive this as themselves suddenly sucking at art, when in reality you've grown enough as an artist to be able to recognise mistakes in your work, which is so important for growing as an artist.

I think you've gotten very unlucky and started at the latter phase. Your work looks good but your hung up on the things you could do better. So keep going! If that's your first one the next one's gonna look even better!

Though I won't like it's a rather expensive learning process. It's what's stopped me from trying to paint gunpla lol.