It's funny how the guidelines switch back and forth. When I was a baby, my mom started me on solids around 3 months.
When my first two were babies, it was 4 months.
Then it changed to 6 months. However, because everything was ok with my first two and weaning at 4 months, I knew it would be ok to start Chase at that time too.
Honestly, you do know when your baby is ready. I've seen a drastic change in Chase from week to week. Yes, there were times when he just didn't want certain foods, but by trying him again a few days or a week later, he was more interested. Babies will let you know when they want something and when they don't.