Awww, I'd love to see some photos of her! Along with Casper, I have Juno, an 8 year old mix-pincher but he's very big. Last time I checked, his weight is almost 25kg x_x
Fortunately, he's a very good boy, aside from the first nudges, he's been real gentle with Casper. Avoiding conflict (Casper sometimes likes to play bite), a few close nudges when he's in a playful mood (which I intervened, because I'm afraid of accidents😂), and just a mild warning when Casper accidentaly went too close to his food. I always monitor their interaction and I think Juno understands that Casper is still too small to play with him.