Almost anytime of year is good to cruise, but Hurricane season is from June-Nov, but even then, you'll never be close to the bad weather, you may miss a port or two if there is any bad weather, but safety comes first.
Here is a link to to some great tips for a first cruisers:
Just a note though, if you are cruising with kids, the school breaks have more families/kids than other times, so keep that in mind. I personally like to cruise in early spring, still cold here and always warm/sunny in the Caribbean, but thats just me. Hope this is some help, just post any questions, someone will be able to help you out :-)