I feel so bad right now I'm almost 30 and never had a cavity here it is my son isn't even 2 yet and…

I feel so bad right now I'm almost 30 and never had a cavity here it is my son isn't even 2 yet and I saw what I think is a cavity in his mouth I feel like a terrible parent because I didn't even know it was happening or I would've done more to prevent it...where's the kid handbook when u need it...😩😓☹️