Tell me about cows milk/fat etc?

[FriedEggyAndSlippery]

I'm confused

I knew all the right ages etc with DD (she was FF from 8m and switched to full fat cows milk at 12m) but now I've totally forgotten.

DS is 19m and still BFing twice - morning and bedtime - decided to cut out daytime/on demand feeds because he was driving me crazy with tantrums about it :(

He eats loads of cheese, yoghurt etc so I'm not worried, but when we were out today I gave him some cows milk and then realised it was semi skimmed. Is that ok once in a while? He has SS on his cereal as well but now I'm wondering if it should be full fat?

If it's relevant he's quite big - not in a chubby way but certainly have no worries about his growth. He was a massive newborn but has since gone down the centiles towards average (I think - I don't weigh him much)

Once in a while I doubt it will harm, don't worry :)

Guidance is full fat from a year, semi skimmed ok from age 2. This is for drinking but also on cereal etc.