Part of learning, even with the help of a teacher, is being given enough space to figure things out yourself.
When you’re asking someone who isn’t a teacher by trade (maybe a friend or a colleague) to help you learn something though it can be a difficult balance to strike.
You don’t want to start checking in with them on every small thing, but they may feel awkward jumping in and giving their opinion on things without you asking them first.
Better then to give them the ‘permission’ up front (‘tell me!’) to jump in when they see something that warrants their opinion, particularly if it’s a crippling mistake (or potential mistake) in their eyes.
Oh and you should also promise you won’t take it personally too (and you shouldn’t).
You are always free to reject the feedback of course, but better to hear it in the first place and give yourself the opportunity to realise that you might just be wrong on this one.