Is it okay to deliver the book in person rather than USPS?

I sold a book online and noticed that the address the book needs to be sent to is only 20 minutes away from where I live. I know now to be stupid and meet them at their house alone but do you think it’s okay to deliver it to them personally instead of USPS?

Also if I do decide this, any tips to avoid complications like saying I never delivered the book to them and wanting money back?