How old is lilo from lilo and stitch?

In film order: In "Lilo and Stitch" she was approximately 5 years old, in "Stitch! The Movie" she was approximately 6 years old (because it technically came before Lilo and Stitch 2 in release), in "Lilo and Stitch 2: Stitch has a glitch" she was approximately 7 years old, and finally in "Leroy and Stitch" she was approximately 8 years old.

The TV series was set after "Stitch! The Movie", so therefore she was approximately 6 years old then too.