medical community is that there is no need for solids before 6 months of age. I also know from experience that you need to pay attention to your child and meet his or her needs regardless what the doctors and nurses tell you.
There are all sorts of articles and guidance about signs of readiness; my boys simply showed interest in food and signs of hunger and they were able to successfully swallow the food, so I allowed them to eat.
As someone who loves to cook, making my own baby food was more a reality than an option. I never really contemplated buying baby food and when I had an opportunity to compare the jarred food with the homemade, it quickly became apparent that homemade food simply tastes better. Never mind that you have so much more control over exactly your child is consuming.
Quinoa, I'll be using the method from Quinoa 365, which I will share with you after I test it out!