Pressing F5, I was able to view your video several times. While the close-in winds seem tame enough, there appears to be gusts further out—consistent with 12-17—that would give me pause. As a "senior sailor", my first question would be:
Video never gives a good impression of weather conditions. But some things I might consider:
1) Is the wind onshore or offshore?
2) How much chop is there?
If the wind is offshore, and there is a lot of chop, I might hesitate because it can be hard to claw your way upwind when overpowered.
3) What is the situation with the launch/recovery site?
If the site is rocky or otherwise hazardous, i might reconsider, because you can be pinned when launching or have a stressful time getting out or returning.
4) How comfortable am I in doing a righting manouver in those conditions?
I did some sailboat rental in a place near Seattle last month, and they make you do a righting manouver before renting. And if the wind increases 5 knots, you have to come in and do it again. I was slightly insulted at the time, but afterwards I saw the value of it. Its not just that you are able to right the boat, but you know the stability limits so you are less likely to capsize.
A go/no go decision is not just a safety decsion, it is more about comfort level. But the Sunfish does a pretty good job of being controllable in higher winds.
Okay, I had a similar day today, a bit windier (17mph). I put on my kahunes and went on out. It was a nail biter, with 1.5 foot waves. I made shorter runs out and back to stay in closer, so lots of tacking. It was a lot of fun but it was stressful. I was comfortable handling the boat, though. Was thankful for the suggestion of sitting towards the back to get the bow up. I guess I just need to build some confidence. Will make myself go out more often.
With the right combination of wind and waves you can have the thrill of surfing a wave. Of course, this comes with the risk of burying the bow under the wave ahead! I've had a couple of occasions where the bow went deep enough I started to wonder if the boat would capsize, pitch-pole, or a combination of both.