Beginner’s Luck?

My first loaf. I thought for sure it would be a hockey puck 😂

I bought dehydrated starter from a friend. Rehydrated it three days ago. Then I was shown an 8-hour loaf recipe and decided to try it out today.

100g starter
475g bread flour
325g warm water
10g salt

Four sets of stretch and folds, 30 min apart.
Bulk fermented for two hours in a bowl on a seedling heating mat (my house is cold).
Shaped, then 20 mins later re-shaped.
Into the fridge for 3 hours.
450 degree oven with lid on for 35 mins, then lid off for 15. I let it cool for 1.5 hours before I cut into it.