Grover would've been born in 1977 because he was 28 when Percy was twelve. So if you do you get 16 and if you do 1993 (the year Percy was born) and subtract 16 from it you get or which should equal out to the year Grover was born.
Percabeth moments <-- Yeah, Drew, go in your corner! oh, leo. my favorite percabeth moment was the underwater kiss, duh! it was so romantic. comment below your favorite percabeth moment! Best underwater kiss ever
also it isn't a tattoo. It is a scar, do you really think the gods tattooed people who became part of the Legion, no they burned their skin, Percy said it burned, tattoos don't burn they sting a little but don't burn