
I had a 13yr old dog when I got my puppy (who is now 2 years old and sadly we've lost the oldie). Oldie was given all the space he wanted, using baby gates to keep pup away from him when he wanted peace.
Pup used to play rough with oldie, I felt so guilty that oldie didn't need to be dealing with all that puppy behavior that I made the dreadfull mistake of interfereing and stopping the pup. All that did was ensure the pup never learnt proper 'doggy' manners with oldie. So, I bit he bullet, after hearing the same advice over & over again - -don't intervene. Amazing - oldie learnt the best method to stop pup being OTT, so I only ever had to step in if things were getting really crazy.
Oldie tried the 'ignore' (turning head to one side & averting eye contact), but that wasn't understood by the pup untill oldie was permitted to follow it through (without my intervention), he would follow through with a bark
(he learnt the specific tone of bark that would stop the pup immidiately, just the one bark was enough),
as pup knew if the bark was ignored then there would be a snap (frightening to watch, but all show). Once left to it, and pup learnt what oldie meant a simple 'ignore' from oldie was then enough to tell pup to back off & leave him alone.
To sum up all of my waffle, I would leave them to it so your oldie can find a way to teach the pup that she doesn't want to be pestered, but at the same time, ensure your oldie has her own space and step in if oldie is really getting stressed.
Dogs teach puppies so much better than we do when it comes to dog:dog behaviour as they both have the same language :)