I am more of an amateur, so I don't mind. My only ambition would be to become more like this guy: https://www.youtube.com/user/Bisqwit
The abundance of online resoures is a mixed blessing - there is so much interesting stuff out there that it's enough to spend your entire life exploring all of it without realising your primary goals.
Think about it like this - if you are a doctor, it's not enought to say you want to be "a better doctor", or "a better sportswoman". Such goals are meaningless, because each and every one of us wants to simply be better. Does becoming a better programmer mean you understand the given technology better, that you code faster in a language of your choice, colaborate with others more efficiently?
You are talking about your career here so I'd approach the problem from the standpoint of the value you bring to the market. On a meta-level your general goal should be acquisition of such a skillset that would be valued and allow you gradually achieve such a high position that would secure your income for the years to come.
Going to a school certainly helps you limit the scope, time and effort you have to put into the task as well as it gives you a diploma that always could be of use. (The market is still unsaturated with coders of any level, but if the demand for manpower dropped a diploma could be important while competing for employment). Schools are also good about teaching more general problems such as math, algorithms and computability theory, these however have imho little use in front-end development.
Try asking people around you what things they think you should learn to perform better in the specyfic set of tasks you are dealing with on daily basis and focus on them. Your employer will be happy to hear you want to improve your skills.
Apart from that try learning something really challenging, something you really don't like doing (assembly? scala?), or something fundamental like TCP/IP or SSH. Personally my weakest point is math, so for me discrete mathematics would be best.
TL:DR Be specyfic in your goals whether you decide to go to school or not.