An OASC 'failure' could prevent you from applying again in the shortterm. Why 'waste' an attempt if you already know you won't pass/do as well as you could?
Go away for a year, do as much research as possible, read up, go on visits, join the UAS if you haven't already then apply.
If you went to OASC now and they gave you a 2 year deferral [a 'don't come back for at least 2 years' notice] due to being so inexperienced you wouldn't be happy.