Hi Kelly,
I know how you feel, when I started DD on solids I was very confused and had her on cereal for way too long beofre introducing veg/fruit!
Anyway, I started DD on Baby Oats at 4 1/2 months. I didn't start with rice b/c I didn't want her to be constipated and she is now 6 months and LOVES solids. I would think that your LO is ready considerdering how much milk he is taking, Sophie was the same and the same weight as your LO when we started.
I gave DD a week to get used to eating off the spoon then I started incorperating solids as a meal, 2 TBL in themorning (when she woke up) and 2 tbs at 'supper'(right after her catnap). After a week I upped her cereal to 3 tablespoons at 'supper'.
After almost 4 weeks of cereal I started to feed her a lunch time meal and used this meal to introduce a new veggie every 2 days then moved on to introducing a new fruit every 2 days. Her favourite out of everything is still peas :shock: ! I probably waited too long to introduce fruit & veggies, not that it really matters now though....
Also DH and I do not have any allergies so I have not been weary of feeding DD anything new. She now eats all sorts of foods and loves Solids!!! She has also been sleeping through the night, 7PM to 6AM with no Dreamfeed :shock:

for 6 weeks!!!
Hope that helps...