I have a 15 month gap between Ds and DD1, then 6 years between DD1 and DD2. There will be almost 5 years between DD2 and DC3. I think the timing has worked in our favour, but it was hard going being 22 with 2 under 2. The older two have been fab and great helps with DD2 and I'm sure they'll continue to be with the next one - DD2 in particular will be soooo excited to have a baby sibling 
I had my booking in appointment on Monday and the midwife took first 1/2 a vial of blood (the vein was pumping too slowly so she tried again) and then took another 5 from my other arm ouch, my arms were sore for the rest of the day and I felt quite sorry for myself!
As I will be 12 weeks a couple of days after Christmas, I likely won't get my scan until the New Year and my midwife is away over Christmas so I won't see her again until the 5th Jan. I'll be 13+3 by then so I hope my scan date comes through a bit earlier so I'm not so close to the cut off either.
Good thing is, though, that I should be able to hear the heartbeat at the next appointment according to the midwife - I never got to hear it so early with the others. In fact I was told you had to wait until 16 weeks, so I am nervously excited about that 