If you are in I class then that is business class and you should get the Biz luggage allowance.
Can you advise the aircraft type? If it is a 747 and you are in 3A then that is a great seat as it is in fact a first class seat
It is more likely that you are in an A330 which means only biz class. I personally dont favour window seats so I normally try for 2E - no one climbs over you and you are close to the front.
If however you like the window then 3A is perfectly fine.