Aww first time mom rin kami dito, kaya naiintindihan ko! Kalamansi juice is okay in small amounts for a 3-year-old, pero honestly sis, kung may ubo na siya it's better to check with your pedia first kasi hindi alam kung ano exact cause ng cough niya, baka viral, baka may ibang kailangan. I usually give diluted juice lang and warm water muna, pero your doctor talaga ang best mag-advise para sa case niya!