Just be patient with your older dog, she'll come around. I went through the same thing 3 times over the last 10 years. My first Dobie was 8 yrs when I got 11 week old Roxy. She did not like her at first and at best just tolerated her. Every time Roxy would go near her she jumped away. Little by little she warmed up to her and they became inseperable. 2 years later I got Alex. He was only 6 weeks and Roxy thought he was her puppy but my older Dobie wanted nothing to do with him. She growled and ran from him when he came near. After 6 months she finally started liking him and played with him. Last summer I get Suzy, she is 8 weeks. Alex loves her immediately but Roxy growled and even nipped her to keep her in line. I did not leave her and Roxy alone but now they play very well together and all of them eat out of the same bowl with no growling. I just get a kick out of seeing them kiss one another. Someone once told me that the older dogs know it is a puppy and won't do them any harm but still I kept my eye on them and never left them alone until the pup got older.