At the end of the day motivation is the most important thing though. It seems likely that R will better fit your current interests and hence make you more likely to continue the journey so I'd go that way
Like if you google R for loop, the first result http://www.r-bloggers.com/how-to-write-the-first-for-loop-in... is much worse than the equivalent first result for python: https://wiki.python.org/moin/ForLoop
