Hi! I think I posted this in the wrong section earlier, and there aren't any replies, so I figured I'd move it over

So we have inherited a young Dutch Shepherd or Dutch Shepherd mix named Russell ("Russ"). He's under a year old. He has learned some things and missed out on learning other things. Life happened. He is a smart dog though because he seems to pick things up pretty quickly.
We're working on potty training and walking on a leash, but he *does* know his name and some commands like "sit". He has good bite inhibition, but he is also all legs and only used to one other dog who was young and big.. so his idea of saying hello to a dog is just spearing right over at top speed. "Yay, let's play!"
We are trying to introduce him to our 13 year old Boston Terrier, Rosie. She finds a huge young dog galloping her way to come sniff and play pretty scary. Her eyesight is also not fantastic anymore. So yeah.. It's a little challenging.
She doesn't really want him near her just yet and tries to basically avoid him. She is fixed btw. Russ will be but isn't yet.
That said, the walk today with both of them together went pretty well. He just *really* didn't like wearing a collar, and it took a bit for him to stop trying to reach Rosie to sniff.
That said, there was a cat on the street and he completely ignored it. He was very interested in Rosie though so maybe he would have reacted to it had he not been preoccupied.
He's very good driven, so it helped us distract him.
We intend to do more walks tomorrow (and every day) but we're keeping them separate for tonight when we're asleep just to be on the safe side..
Again, he is a rather sudden surprise addition to the family.
Rosie got pretty shaky when he got closer, and I don't want to blow things due to potential fear aggression. (From her, not him)
He calms down pretty good once he's had the chance to explore to his heart's content.. and he is a huge cuddle-bug (!!!).
I'm sure over time he will be a relatively calm dog, since he was pretty calm when the newness of being with us cooled a little..
He hasn't shown any signs of aggression whatsoever, but Rosie finds him scary so we're taking things slow.
She growled at him when he got too close too quickly.
He doesn't really seem to get the hint though.
Since he doesn't know commands like "leave it" yet either, well.. puppy classes.. ASAP.
I think in the long run they will get along really well, he is clearly a very gentle natured dog, right now she just finds him a little scary. It's just more challenging because of age and size mismatches, and issues with socialization.
So meanwhile any suggestions to hold us over until classes start would be very, very welcome..
Thanks!
Rosie, Russ, and Fam.