For those of you having trouble with audio lag, etc with Rocksmith, make sure you go through the step by step procedures to configure your PC as recommended:
http://forums.ubi.com/showthread.php/802854-Rocksmith-2014-PC-Configuration-and-FAQ?s=3d722553a5b5632f67a1781379e04dabFor the OP, hey I started playing guitar about a year and a half ago when I turned 46! It is not too late for you.
I started because I was intrigued by Rocksmith, and while I enjoy using it (I use the PC version), it is not my primary method of learning.
I use
http://www.justinguitar.com as my primary lesson structure. I have his books/dvds and use those along with the online videos for songs, etc. I supplement from time to time with other lessons. I played the piano for 10 years when I was a kid so I have a good foundation in music theory which is helping a lot.
Rocksmith is quite fun, though, for learning songs. Make use of the riff repeater and you'll soon have the songs down. I've done some of the Rocksmith lessons but don't really think they are that great or well structured, but that's probably due to how I learn.
I recommend trying different online lesson sources and see what works best for you. I wouldn't just rely on the free stuff, though, or you will be missing out on a lot of necessary info.
A real live teacher might work for you, too. I didn't want to go that route because I didn't want the hassle of "auditioning" different teachers to find my style, and I remember when I took piano lessons--I hated it and it turned me off from music for many years. What I am doing now is fun for me and I am learning a lot. I enjoy practicing which is more than I could ever say about the piano.
Good luck.