Depends on how you go about it. If you buy the boat, hop on board and head to Mexico, you're probably crazy.
However, if you take baby steps while learning, test yourself, test the boat, learn navigation, learn how to handle bad weather, learn, learn, learn then you're not crazy and you'll have a blast.
Take short trips at first, point A to point A, increase to overnighters to give experience to yourself and your crew (you DO have crew, don't you? IMHO ALL ocean-going singlehanders are insane.)
Join the U.S. Power Squadron and take courses. Learn how to fix everything on your boat. Prepare yourself and your boat. Take your time... or take your life. Your choice.