Hi Brayden,
This is not a bad effort for your first try with a DSLR camera. Long exposures of water can often be unpredictable, particularly if you are working around the sea.
The variation in shutter speed (from 5 seconds to 20 seconds) can make a big difference, as can the moment when you decide to make the photo. So, experiment with different exposure times and moments. Try making the photo at the start of a swell and try another photo as the wave recedes. All the options are open to you.
Given that you are exploring with filters, perhaps the other filter I would look at adding to this mix is a one stop or a two stop graduated neutral density filter. This will darken the sky for you and help keep the viewer's eyes down on the water. If you made this photo in RAW mode then you can choose to add a graduated neutral density effect in the RAW converter. This is often the better option because you can control the effect more easily and opt to remove it if you feel the effect has not worked.
Now, as to how you can improve this image, I would be inclined to crop this image down to a panorama. Lose the hard rock in the foreground and lose some of that bright sky. As soon as you do this you will discover that you eyes are no longer racing between the sky and the foreground; they are now enjoying the milky water effects in the centre of the photograph.
Make the most of that DSLR,
Cheers, Anthony
Image Doctor's edited version
