That's good.
I'm not sure what the target was but I'm sure it'd still taste good at 1050.
Depending on the final gravity after fermenting 1050 could give you a 5%+ beer. If you added the water to take it to 5g and dropped it to say 1040 then I'm sure it'd still be about 4%.
It depends what's most important to you. But if the beer kit is designed to give 5g then adding the extra water will still give you the % and body it's designed to.
Your brew will have more body and a higher %.
It's gonna taste spot on no matter what you do.!!!!!!