Clueless about solids,HELP!

My lo is 3 months now and pediatrician talked about starting solids at 4 months IF she is showing signs of readiness. I am hearing conflicting info though about waiting until 6 months from other mothers. What has everyone's pediatrician recommended? And my husband wants to start with oatmeal in THE BOTTLE. I truly feel that would be a choking hazard?! Any veteran mom's have advice or different recommendations on when, how, and what is best to start with? I do not want to start with rice cereal is all I have really decided on.