As Strider says, it depends on everyone's experience of fellwalking in general, but I would have reservations. Latrigg will probably feel pretty straightforward and create a sense of security, but Skiddaw would be considerably more effort. The path is easy to follow but very hard and stony. If someone gets sore feet around the top of Skiddaw, it is a long way back and they won't enjoy it.
I would consider something like Causey Pike from Stoneycroft as a first Wainwright. It is a bit more challenging than Lattrigg to start with, so you will have more of a barometer about what the children will be comfortable with. There is more variety in the route - including a minor scramble - to keep interest up. There are options to extend, such as Outerside/Barrow and Sail/Eel Crag, which can be evaluated having gained more height early on.
I don't mean to be negative about the Skiddaw route. It may be perfect for you, but if you are not sure I would be cautious: it sounds like the last thing you want to do is put them off!
As Richard says, Catbells is another good option nearby, with lots of route options. The whole ridge up to High Spy is a good shout if in the mood.