Time travel is by far a speedster's greatest power. Mastering it can take years... years which we don't have.

[ he starts off, leaning against the wall of his cell beside his console, as he contemplates the request just made to him. all it took was even offering the slightest hint of who her father was to make her ask if there was any way she could meet him. and though he could easily say no and shoo her off, that clearly didn't work the first time. if he truly only has an hour left before he goes, he may as well not stare at the timer, listen to the ominous digital tick it makes with each passing second. ]

Luckily you don't need to be a master. You just need to learn how to not screw up. I can teach you, but only after you prove you can do it.