Learn the basic scale of guitar(Do Re Mi Fa Sol La Si Do), it also will help you to go fast.
The scale is like this(lol I did this "sketch"):
Also, do the "1,2,3 and 4" in each space, in each chords.
Example: 1st finger at the 5th chord, in the 1st space.
If you are so slow, AND wants to play something, not doing the "1,2, 3 and 4" like I said before, play some basics intro musics, like:
Come as you are
Seven Nation Army
Nothing else Matters(this is an very important guitar fingering exercise for beginners)
If you want to play an entire song, after training some intro of Nothing Else Matters, I think you can start with Black Bird(The Beatles). it's was my first too.
It's a big help, I think, because I never played on rocksmith, I just saw people playing it, also I'll buy it soon.