Depends what you want to use it for. If you just want to play with new features and learn stuff, go right ahead! Whatever you do will be useful in the future.
If you're aiming to sell software, and want to have a large target market, it might not be the best move right now. According to steam hardware survey, only about 5% of users have dx11-capable systems, while over 50% have dx10 now. Keep in mind though that this is survey of steam users, who more likely have gaming-capable PCs, so the total market situation is probably worse.