Should I get ios 8.1.3 on my ipod 5?

Hi so I have ios 7 on my ipod and i want to know if i should update it to ios 8.1.3, here are my questions:

1. will it mess up my ipod at all? like lag, and just a bunch of bad things?

2. if the update fails and delete my stuff will i have lost all of my videos? i bought the 20GB icloud storage yesterday and backed everything up, so did it back up my photos AND videos?

thank you!