Welcome to Styleforum Function. Extend your hand forward as though you are about to shake hands with someone. Your shirt cuff should rest upon your wrist line. With a jacket on, a sliver (1/8" to 1/4" visible..some men will accept 3/8" to 1/2" ) of shirt cuff should be present beyond the jacket cuff with your arm at rest by your side.
Your cuffs appear to be just fine. Some may say a tad on the long side, but I find the sleeve length acceptable. Just be careful when matching a jacket. Mind the jacket sleeve length with this shirt as per the guidline I have just given you. Congratulations on your purchase. Hope this helps.