This looks incredible. New character?

yes 🤫

What's her name?

Sofia. But I still need to define many things. It is a work in progress

Cool. Looking forward to seeing more of her.

I'm not an expert of artists, but I believe the real talent, what proves someone being an artist is that they can create very appealing artworks using just a few lines.
Like this you made!

I see where the sky is, the ground, the water, the umbrellas, and most importantly, I see a nice and casual character which makes me smile.

I don't even feel the need of more lines, or shadow, shading, not even color! It feels it is good as it is!
The true talent of a artist!

Personally, I am a very demanding person with myself, I know I can give more.
I will publish groups of sketches, maybe this way it will help more future artists with examples.

And it does even more!
You're right about being demanding with yourself. That forces you to improve. Just don't let it stop people like what you did, even you're unsatisfied with the result.
Like this artwork you made!
It surely made ME smile! :)
Could could have scrap it to nothing, or just not posting it, saying 'It's quality not match to my art level!' You would deleted it, and it would have given joy to NO ONE.

And of course, there really is a specific quality level that should not be posted, maybe for educational reason or so.
Just keep in mind that after you've judged your artwork from your demanding perspective, then, try to judge it again from a general viewers' perspective too.

In the worst case, if you really post something utterly awful, xD You still can delete is later, knowing that your artwork had the change to give joy to anyone else, even it gave no joy to you for some demanding reason. ^^