The advice Sailing Dog gave is correct. Wind over tide out in the Gulf Stream is NASTY. But it really concerns people trying to get from Florida to the Bahamas by riding a cold front as the prevailing EASTERLY windflow will usually turn westerly as a cold front comes through but then can go North very quickly giving you the wind over tide situation.
Cold fronts are most common from November until Spring and can bring both stronger and changing winds. What I almost always see as cold fronts come through is the
wind will begin to clock around from the southeast to the south. As the cold front gets a bit closer, the wind will continue to clock, usually quickly through the southwest, and
west, usually fairly light and then blow stronger out of the northwest as the front gets near and stay there for a while. The winds will continue to clock to the northeast and
possibly increase even more in strength as the front passes. Winds will continue to clock around to the southeast and usually moderate as the front moves on. The northeast
wind can last a while and cause "rages" at many of the passes where the deeper ocean meets the shallow banks.
I presume you are thinking of making this passage in the next few weeks. Just check Windguru and make sure you have winds between ENE and S with no named features lurking close by. These would be the norm.
Why do you need to sail at night?
Well West End to Fort Pierce is about 90 miles, allowing for the Gulf stream you are going to sail about 75 miles so at 5 knots you need 15 hours at 6 knots you need 12 and 1/2. Don't push the boat; it is early days for you and reefing down a little and keeping the speed around 5 knots allows for a sudden increase in wind speed.
You want to arrive at about 10 am so the sun will be over your shoulder as you enter Fort Pierce making it easy to see where you are going.
Sailing overnight also allows for you to have a slower than expected passage only averaging 4 knots and still arrive in daylight.
Please do not try to enter a strange harbour or inlet at night, in fact any night entrance is a high risk activity, countless boats have been lost attempting them.
Oh Yes just one thing more to make you take even greater care; I believe if you sink or strand in Florida the coasties will charge you something like $24k a day until you remove the wreckage and clean up any spills.