I'm pretty sure that the signs of readiness are not age dependant but baby dependant. These are:

Can sit unassisted.
Can grab and hold food.
Can get food into mouth.
Does not tongue-thrust food out of mouth.
Can gum/chew food (having teeth is a good sign, but this is less relevant after 6 months, since a 4 month old who cannot sit and has no teeth probably isn't ready, whereas an 11month old who can WALK but has no teeth certainly will be!) and swallow.

Research indicates spoon-feeding isn't the most useful way to begin for most babies, and really with #2 i'm not going to worry about any of it. I'm going to eat wholesome foods and let #2 be in reach of them from whenever it's necessary (like i'm not going to try to eat stood up away from DD while she moaned for the boob like i did first time around - i don't think she saw food that wasn't toast for the first 7 months of life!) and if they are showing the signs of being ready, and grab and try some, WHATEVER age they are, that's ok with me. At the point when mummy's belly is still rumbling after meals because bubs has half-inched a decent portion, bubs will be getting their own portion.

I am leaning quite strongly towards being baby-led in all things. I have personally never seen a 4 month old who could sit unaided and use a pincer grasp to manipulate food and eat, but no doubt they exist occasionally. MOST babies will not have the signs of readiness much before 6 months, but some might, just as some will have no interest before 7 or even 8 months. Pay attention to your baby.

For those who KNOW there are allergies in the family history waiting until 6 months, regardless of readiness, isn't going to do baby any harm. Most babies will not be displaying the above signs before about 5-5.5 months and a few weeks is nothing. For those who aren't sure about their family history i suggest you read not only the guidelines, but the studies behind them. When you read a guideline you are reading an opinion of an individual or team of individuals, based on their understanding of the study and their own experiences. As a parent YOU will be responsible for whatever outcomes your actions have for your kids, so it's perfectly ok if, upon reading the study, you come to a different conclusion.

Bx