Honestly, that's a really common worry, especially first time! Usually kung ang baby ay having a hard time latching, lumalabas lang ng konti ang milk, or ang baby seems frustrated during feeds, those can be signs na maliit yung opening, but mas better talaga to check with your OB or pediatrician directly kasi they can assess properly and may solutions like nipple shields o techniques na makakatulong. One of my mum friends discovered hers was actually fine pero ang latch lang ng baby ang kailangan i-adjust, so kaya don't stress too much yet, mamsh, maraming ways to fix it!