my first loaves looked a lot like this. this is underproved, which is why you have that big gas bubble at the top (overproved can look similar sometimes, but will have a shaggy crumb). even if it seems to be taking forever you gotta let it prove until its done.

i've had proofs go 12 hours or more, especially on cold days. it's nerve-wracking sometimes. but, in the worst case, if it overproves too much, just make focaccia.

hth!

eta: young starters can take a long time to prove, as well. so the more mature your starter gets, the easier this becomes. when my starters are strong, they'll treble in size in like 4-6 hours, and that's when i bake with them. my starters are also quite old at this point, since they were born during the covid lockdowns (the starter baby boom).

This is pretty damn good for a first attempt!

Very good for your first one! Try getting more steam and heat in the oven and/or protecting the dough against drying out before baking. You can see that the full raising potential was not used up, the sides rose because the crust formed too quickly.

Also proofing longer might help as another person here suggested.

Keep going!

The important thing is to constantly talk about your “starter” like it’s a child and everyone else is related to said child.

No one really makes bread. I mean there are bakers and people do eat bread…

But no one knows them and everyone tends to a starter baby who “allows” them to make “bread” and “pretzels”. Bread tho is too hard. Sourdough starter is your master. You want biscuits, rolls, loves, pretzels? Well you only get sourdough.

In return there is no other bread. No one bakes bread, they only tend to starter to make sourdough. The starter must live….

Then you discover scobies…