Is it wrong that I'm thinking of using brain cancer to lose my virginity?
How would that help you lose your virginity?
Because I think that cancer gives others a strong sense of urgency
Most people will have sympathy for others who are dying, but you shouldn't be trying to pressure them into having sex with you.  If you let people know that you don't have much time left, they will probably want to help you be happy, without you having to appeal to their guilt.
It's fine as long as I get my fuck.
You will get sympathy and people who care for you because you are dying and that's normal but just try to not take advantage of people.