Mildez.. Sounds like your doing great already!
I have previously owned working breed (a collie and a kelpie) and they are so easy to train, I did agility training with my dogs and they were excellently trained!

If I could give you any tips it would be:

1. Find what motivates your pup, whether it is food or a favourite toy or a game (such as fetch, where is they do what you want you will throw the ball for them to fetch), once you know what they like they will do absolutely anything for you, and once they realize that doing a certain thing results in their treat then they won't stop doing it.. (I once made the mistake of laughing and giving my Rotty a treat when he stood up on his back legs and did a little dance and to this day as soon as he sees treats-up he goes!!)
2. You don't necessarily have to buy 'dog treats' I found that my dogs absolutely loved Devon! I just went to the supermarket and bought a Devon log for about $5 and chopped it into little pieces for training.. It works better them dog treats, for half of the cost!
3. Teaching your dog to sit is simple! When they are standing in front of you, show them the treat and put the treat above their nose (just out of reach) and move the treat over their head toward their bum, in a semi circle motion.. Your dog will lift it's head up to get the treat and when you take it over the dogs head it will back up and eventually sit.. The key to this is .. As soon as your pups bum hits the ground say 'sit' and then give the treat and lots of praise and repeat, repeat repeat!

As long as you make it clear to your pup what you want they will do it

I hope you have fun teaching her and make sure you teach we early that jumping up and running into the kids is not acceptable!