Novice Kayaker

Hi, 
Looking to join a group of kayakers who go out once a week in the bay of islands for an hour or 3. Most are sit in kayaks. No fishing, camping etc. I am less agile than i was and not as fit. I am also a relative novice, but wish to join and do not want to be left behind, so a faster kayak will be needed.
Some have suggested a sit in kayak of 5m length with a comfortable seat (see attachment).
But, Would a "beginners" surfski be appropriate?
Any advice would be appreciated.
Thanks

A beginner surfski will be about as fast as a decent sea kayak. Any ski much "faster" than a good sea kayak will require a certain level of skill and fitness. If you don't have the required skill and fitness; you will actually be slower than if you paddled a sea kayak. Surfskis are great fun but they are not as versatile as a well designed sea kayak.

I guess it depends on the group you paddle with. I joined a kayak group and they restrict the boats to no rec boats, at least 14 feet with sealed bulkheads, paddle skirts, and lights. I paddled my surfski with them once and I gots lots of dirty looks. I couldn't stand waiting for the  slowest paddler to keep up, so I stopped paddling with them. I like to paddle about 6 mph unless I'm racing or doing intervals. 

So, if your group is anything like that, a beginner surfski like an Epic v8 or Nelo 510 would be great. Comfortable, stable, fast, and easy to paddle.

In regards to being faster in a beginner ski, I wouldn't count on that. At that level it's 99% about your paddling ability. I have been left in the dust by seasoned sea kayakers while being a novice in a V7 more times than I can count. The cruising speed difference between beginner ski and a decent sea kayak is not really that significant and chined/rockered sea kayaks may have an advantage in confused rebound conditions.
But. If you feel like doing it with a stable ski, by all means go ahead. These are comfortable and fun boats. Just don't expect miracles.