Very nice sunset. However, the near vertical clouds on the right and the near horizontal clouds just down from the top on the left (contrails perhaps) defeat the composition. Using these as natural guidelines, and cropping just inside them, would have made a much more dramatic shot.
Half Moon Bay is a beautiful place, and this is a lovely capture. The colours are beautiful, and the sun is relatively muted without sacrificing detail on the water.
First time taking a sunset? Well if it is, good job...next time try different apertures...especially small ones such as f/18 to get interesting effects on the sun.