I know my relatives have money I could borrow, but I'm having trouble getting them to see past me being younger and so forth. How would you convince your relatives to invest?
Success is the best evidence. They might need to see you do a few deals successfully before they get interested. You can always go out and forge new relationships with potential investors. Go network locally! I started a meetup to build a community and meet potential investors for my deals. It's going well so far!