Mint, I don't think 17 weeks is too young to go through the night. Pepsi did from about 10 weeks old. But we don't put her to bed until 11.00 ish usually and then she wines at 7.15 ish at weekends (we are up by 6.30 in the week anyway).
I can finally feel that Pepsi is going to be a fantastic addition to our family. She is now around 20 weeks old and have finally settled down. She still jumps up and nips but not as often at all. We can finally relax in the evening 
She has learnt to ask to play nicely (brings toy and drops it by us) rather than jumping up nipping and pawing.
She has learn to sit, stay, wait and leave. We can walk through the back door and out into the garden whilst she waits, can leave treats on the floor and not eat them until she is told to.
Still have a big problem with walking on the lead and her recall has got worse, but we've been asked to go to a special training session where she will be used to help train other people (typical springer who pulls and looks down apparently, but has enough control in other areas to be usefull to the trainer.
I can't believe how different I feel about her now, I just didn't bond with her until recently, felt very odd about that but all good now.
She is a lovely dog, just a bit determined 
Good luck with all the pups, especially those in the early days, it's hard but so worth it.
Our task from the puppy training class this week is teacher Pepsi to do a trick!! any suggestions?