Is it ok to forget?

Yep, that’s what the SRS is for! If you forget something, it drops you down a level so you get the item more often. If you get it right, you go up a level so you get it less often. Read about leeches in the forum for when forgetting becomes a problem (it’s too soon for you).

That said, it’s a good idea to focus on mnemonics and such (make up your own and put it in the notes if necessary) from the start, so that you forget less. In my experience, it can take a few levels to get “kanji brain” where you’re able to recognize radicals (instead of being overwhelmed by seemingly independent strokes). Separately, it can take a few levels to get used to using the mnemonics and memorizing efficiently.