My son just turned 1 year old a few days ago and I am planning to start introducing him to cup milk feeding instead of bottle feeding. Is it too early or is there any tips to help this transition of bottles to cup? Thank you.

Yes he can already cup feed. Cup feeding is recommended even in premie babies in NICU and newborns. You can try small amounts first or in a small cup like a medicine glass or shot glass then eventually move to a bigger glass/cup