potty training my 3 month old

Question
We have had our cocker spaniel since she was 7 weeks old.  She is now 15 weeks old.  She is still going inside potty at least 50 % of the time.   We have a year old golden retriever that is indoor also and she never has an accident.  Our golden always goes to the door and stands there until we let her out.  Most the time the puppy doesn't want to follow and constantly wants to be in the house.  Our cocker will play outside for 20 minutes and then come right in and pee less then 30 seconds later.  It is very frustrating.  I have wood floors and often there is little crumbs here and there, it seems like she is always sniffing the ground. How do I break her of going inside when she goes outside just fine too.

thanks  

Answer
Partly it may just take a little longer.  Are you going out with her and praising her when she goes outside?  If she goes to the door at all, do you praise her?  If she never goes to the door and waits, start praising her and taking her out if she gets near it.