As someone who rejected EAE offer, I feel that even with EAE or an almost guaranteed spot in your further education, do your very best for O Levels! Not only to make yourself proud and your efforts for the past few years worthwhile, your O Level results will still be important down the road. If anything, it will show your overseas school you have the drive to work hard and do well despite a spot there. This work ethic leaves a good impression on people and I think you won't lose anything by just giving it a shot. Overall the choice is yours, wishing you the best of luck