Should I take a major risk that has the potential to bring about great happiness?

You can figure it out using your head, not your heart. Make a pros & cons list and try to avoid fear of risk and overestimation of gain. Will it cost not much and failure won't be tremendous?

Are you likely to succeed? How much of the risk can you control and how much is factors you have no influence over? If it goes badly can you spot it early & get out?