Salam! At that age memang macam tu, dia dah makan proper food so susu jadi less priority sikit, tapi as long as dia makan bagus, tu dah ok lah. Just keep offering susu dalam cup or bottle without forcing, boleh juga try mix susu dalam makanan macam porridge atau pudding if dia really refuses to drink. Kalo dia active and growing normally, jangan worry sangat, tapi boleh lah check dengan pediatrician just to confirm everything's on track!