In the actual year of the series (X793) Wendy has 14 years old, Sting and Rogue 21 years old, and Natsu and Gajeel´s age is actually unknown (probably between their 18 or 20 years old).
Goku and Chi-Chi's relationship has never been normal, things were weird right off the bat. When Goku first met Chi-Chi, they were only kids. Chi-Chi quickly fell in love with Goku, who was completely oblivious to her feelings. But, this naive mistake didn't deter Chi-Chi's feelings, and she took the proposal to heart.
Goku doesn't really care about Bardock. He's never even met him! The only father he respects is Grandpa Gohan.