I know Flair makes scale and sport scale kits of WWI and WWII planes, and Sussex Model Centre sells them.
http://www.sussex-model-centre.co.uk
I have no idea how suitable any of them are for a first build. A lot depends on how scale you want it to be. If it just needs to have the basic outline but you don't care about full cockpiits, retracts, sliding canopy, etc; it will be a lot easier to be successful.

Sussex also handles some Top Flite and SIG kits. If the decision was mine, I'd build a fairly simple kit first. That way you learn a lot without getting bogged down in fine details. You may find that you not like building. If you build a trainer or 'second plane' you can probably sell it to a club member or new guy if you are not interested in flying/keeping it.