If you look in the FF8 instruction manual it says that Laguna is 10 years older than Squall. Meaning Laguna was only 10 when Sqaull was born.
Look at the attachment.
He's 10 years old during his scenario, which took place before Squall was even born. They were trying to make it seem, during the game, that it was happening at present time, which it wasnt. Laguna is clearly far older than Squall in present game time.