If time is a tunnel you can detach from and reattach to, then you can go back in time and literally clone yourself (there's you with time travel and you who has not yet been given the choice). The previous you and yourself now share a new timeline. The timeline in which you chose time travel is in another tunnel. You can go back to it, but you wanted to get invisibility so you returned to the past of your original timeline. You go to the origin of this Invisibility or Time Travel choice before your younger self does. You choose invisibility. Now you have time travel and invisibility. Your previous self that you now share a timeline with never gets the choice because you stole it from him. There is you, who can time travel and become invisible, and there is your previous self who never gets the choice and lives his life normally. You can essentially be your own guardian angel now. Either you ditch the 'original clone' or guard him.