I moved abroad in different circs - followed my French DH back to his native land. Obviously didn't go nearly as far as you either so my experience is probably irrelevant BUT as gregs says - it is as scary as you want to make it. If you can keep an open mind, feel that you can integrate well (NOT just that you are nice friendly people, which I am sure you are, but that you will be able to pick up on and understand local social niceties and adapt accordingly i.e. be willing to adopt the when in Rome approach) then you have nothing to fear.
The bigs things like missing family and your ability to call your new country 'home' are the deal-breakers. It is important not to get too wrapped up in the details, provided they meet your basic requirements, like customs, schools, healthcare, etc as most civilised societies should be able to accomodate your needs (but they may differ to those you are used to in the UK). I say that as someone who is constantly posting on these boards asking for help understanding the minutae of French life (or lurking on other people's threads).
Finding a job is important - or at least activity to keep you busy.
My personal experience is that I fell pregnant within six weeks of arriving here, felt ill for three months and then worked like a maniac up until the end of pregnancy. I went back to work early (took min mat leave) and to be honest, having a baby, being tired, stressed and having a very full-time job, means that I don't have a lot of time or energy to put into making friendships, which can be quite lonely at times. I have made about four really good friends (and obviously have DH's too, and he's got lovely friends). Obviously with an older DD you may find it easier to meet people, or at least be forced to, for her sake, which is no bad thing.