all babies really need for the first year is breastmilk. she's telling you she's not ready. take her cue, mama, and don't force it. she doesn't need solids for the nutrition; it's really only about the experience at this age.
it's ok to keep trying, but don't expect much. though i started when my daughter was 7.5 months, she didn't start eating much until 2 weeks before her 1st birthday!
Breastfed babies are used to sweet mama's milk. If you want it to be a good transition, start with bananas, sweet potatoes, and avocados. They are nutritious, but more sweet, like breastmilk. Also, she might not want it mushy on a spoon. I started my first son on solids at 7 months, but he didn't really want them until 10 months old, and I discovered that he wanted to feed himself only. Many babies don't eat much until they can self feed, so tiny soft (super ripe) chunks of banana, sweet potato, or avocado that she can pick up herself might be more in order. Just expect a mess. Oh, and banana stains like you wouldn't believe! Black mess!
Don't worry if you're not following the "regular" routine that some pedis suggest. Believe me, following my children's cues and introducing them to sweeter veggies and fruits more like breastmilk was the way to go - they love their veggies and have always eaten them. In fact, my son's favorite veggies have always been broccoli and green beans. Giving them "sweeter" first won't make them hate veggies! Also, rice cereal has very little nutrition. It was developed to compliment formula. They suggest it first because so few babies are allergic to it and it's easy to digest. When you wait until 6+ months like you've done, her little tummy and digestive system are mature enough to handle real food. She doesn't need the rice cereal at all.
She's not picky, mama, she just knows what's good for her and right for her. and that's breastmilk. THe American Academy of Pediatrics and the World Health Organization agree that breastmilk is all that's necessary for the first year of life!
Check out this link on kellymom http://kellymom.com/nutrition/solids/index.html If you've not visited it before, it's a site full of research-based information on all things having to do with breastfeeding. Kelly is an Independent Board Certified Lactation Consultant, and she quotes the leading experts in the world of lactation (like Dr. Jack Newman). This is a resource to trust, and full of great, helpful info!