I have a feeling that somewhere in her books Tracy did talk about using PUPD at 3 months, but the general advice is from 4 months on, and the only after a last resort after shh pat has been tried consistently without success. My understanding however is that shh pat and PUPD are really more of a continuum rather than separate things - as in, with shh pat you try to calm in the cot, but would pick up if needed to calm them down. With PUPD the aim is still at younger ages to calm in the cot, only really picking up when necessary. So not too different! All that said.....I still think 10-11 weeks old is ok not to be settling easily. Both of mine were only just starting to get it at that point, and often needed a lot of help. I found a big difference between 3 and 4 months though - so perhaps start out now with shh pat, keep your expectations low (for now) and just see how you get on?