I don't know what line that is, it could be a Teeny. It is normal for a saltwater line to have a short head as it helps turnover when fishing with big flies.
Is your problem is that you are not sure if the line matches the rod then why don't you try casting it.
A 13wt is a very big gun and in between a normal heavy weight flats rod (12wt) and a blue water rod (14wt).
However if you can cast with it then great.