Absolutely go for it. Opportunities like this don't come along every day. I've done a RTW trip, but I was still working and didn't have enough time to really enjoy it. On a different occasion I spent three weeks in Japan. I bought a train pass that let me travel wherever in Japan I wanted whenever I wanted. That was an amazing trip and I'd repeat it in a heart beat. I loved Northern Japan. I went hiking there with some people I met on the train and I don't think I would have gone there if I had planned out my trip in advance. Tokyo was an adventure, Kyoto was beautiful and had great food, and it rained the first time I was at Mount Fuji so I just went back a week later and it was gorgeous. I don't speak Japanese, but I found at least one person who spoke English wherever I went.

Skip the guilt, do whatever floats your boat, and have a great time.