Wildlife in the wood is very difficult and almost requires a very expensive lens. All the "cheap" telephoto lenses offer f5.6 or f6.3 as max aperture, which will almost guarantee hunting in low light conditions.
Looking for a second hand 300mm (f4.0 or f2.8) prime might be something affordable, but it's going to be a big investment. I'd wait with this until she's sure photography is her thing...