That depends on how you use the word incest. Incest just defines as "sexual relations between people classed as being too closely related to marry each other", or used as a crime for "having sexual intercourse with a parent, child, sibling, or grandchild".
By the crime, it's hence fine to have sex with a cousin. By the definition, it depends whether you think you're too closely related to your cousin to marry them. I personally think it's fine for cousins to marry (though my definition of incest as a crime also stretches to nieces, nephews, uncles and aunts - but then it's variable depending on whether they married into the family or not. If they married in, they're fair game, incest-wise).