Yes Haruka is 10, but Kasumi was actually 2 years older than Satoshi if I remember correctly. I know it's a little kids show but they really should have had Satoshi grow at least a couple of years older in the anime.
Kasumi (12 years old)Takeshi (20 years old)Hanako (30 years old)Hikari (5 years old)Takeshi (18 years old)Satoshi (12 years old)Masato (7 years old)I want to hurry up and become a trainer too.Takeshi (17 years old)Haruka (10 years old)Satoshi (15 years old)Nanako (10 years old)KyahaDashing swiftly through the wind blowin' from Rokko Japanese baseball team, Hanshin Tiger's fight songI don't know what I want to do.thirty years8 more years, huh. I can't wait.squeezeMy body and soul are captured by Master Ibuki! I'm a mere thin-eyed pokemon, Takeshi!It's not like I... (etc)YearYearYear