i know you said your not looking to be crucified, but i think you will be. i dont agree with no earlier than 6m but i do agree with no earlier than 17 weeks!! my LB is 4.5 month and have now started to wean due to reflux (drs advice) and him being very hungry, but 12 weeks? when your LO is fine and (WAS) happy with milk just seems strange to me, a baby doesnt need different tastes or textures, all they need is breast or formula milk..
i dont really know what advice your looking for, nor do i think i could help.. but 12 weeks is far too young, has you LO got full control over their head?