A friend of mine, 26 years old girl, just got back from a 4 month trip all over India. Part of the time she spent alone, and the rest with a friend (also a girl).
From my experience (although gained in South America, but I heard it's not really different all over the globe), even if you're traveling on your own, you're not really alone, and you can always hook up with people you meet along the way, and part from them when you just feel like it.
