How do you know that u have truly forgiven someone?

So i keep running into this boy that I didn't get along with in junior high school,now while i'm in college.But we don't speak however,he either just gives me a head nod, and I say whats up, and keep on going without saying another word. No handshakes or pounds are exchanged and no real words are spoken. Likewise there i saw this girl that i had a few verbal fights with(never hit her because she's a girl,and i'm a guy), a few years ago on a bus, and she walked past me,looked at me and kept going. i didn't say a word to her, and likewise she didn't say a word to me. Have i truly forgiven these people for the wrongs they have committed against me,and have they forgiven me after all these years.