It sounds like you are introducing foods correctly, perfect actually. I should have done the same thing but I jumped right in and introduced them all within the first few weeks. Luckily we didn't have any issues but what you're doing is smart, and you're doing a great job!
Just an fyi, when you get to bananas and apples, they can be constipating (which is why I never give both on the same day). But pears, peas, peaches, plums, and spinach help to get things moving so I usually give him one or two of those things each day to balance out his bowel movements and he hasn't gotten backed up yet... fingers crossed.