Hi Psy
I weaned my boy at 4 months (as this was ok 4 years ago!) So I cant see any reason you shouldn't start now! My boy never really liked milk that much so was really glad to start him on food, I started with rice and rusks!
To be honest, I can see my little girl doing the same as yours, as she taked 1 / 2 oz every two hours, but then has about 3 oz now and again!
She does get to three hours if I occupy her, but she never takes any more anyway! I know she's younger (4 weeks!) but I she's so little, I just think her belly is little and she doesn't want a lot!
x x x