a ducati is more of an enthusiasts bike , i would not recommend a 600 for a first bike . as there is no safety course in your country i could see some problems you will face . get a 250 for a few years experience then get the bigger bike
any 50cc or moped is a great starting point for anyone to start riding , do the safety course and happy riding . once you have your ride you will wonder how you did without it , no more waiting for buses or trains or lifts from family and friends
ducatis do cost a bit more than the average bike but what people overlook often is the cost of maintenance ie cam belt replacement . this must be done at regular intervals and if overlooked the bike is prone to seize .
i prefer jap bikes that's what i am used to and familiar with . someone who is familiar with Harley's would probably say harley so obviously it is all up to personal preference .
probably in the winter as no one will be interested in riding . you can always store the bike until the spring . charge the battery once a month and when you are ready to ride get fresh petrol
adults join a motorcyle club and ask about green laning , it could even be on the internet , a green lane is a place where anyone can go , horses ramblers and bikes . please use extra care when other users are about .