When I saw you wrote in Spanish I was tempted to skip reading your post today, but on second thought, I felt it would be fun to know why you chose to do so. And as an ardent follower of yours, my curiosity got the better of me and I decided to google-translate for understanding.
Before reading far I was struck by an information in the background section of your post: the fact that your Mum is a Steemian! Wow! 
Your decision to study Spanish reminds me of my own decision to study French at some point in my life. Like you, I studied it in the company of some friends. We paid a private teacher to do this. But due to a lack of devotion and some distractions we soon lost interest and eventually, the class disintegrated.
It is amazing that what started as a hobby became that much of a passion as to make you leave school and take up a full-time, independent language teacher. No doubt, your commitment and focus made you excel in the languages, thereby lending credence to the opinion that anything is achievable if only one sets his mind to it.
As I said above, whatsoever the mind of man can conceive he can achieve. To this extent, it cannot be detrimental to want to strive to improve one’s knowledge of a language. If anything, it has been scientifically proven that such exercise is helpful to the mental and psychological development of the brain of the learner. I, therefore, encourage you to continue to learn as much as you can of the language you have chosen. The only thing I will advise here is that you may need to have a realistic and pragmatic programme to ensure that there is no conflict or intermixture, especially if you're studying up to four languages at the same time.
RE: La adquisición casual de habilidades lingüísticas: ¿merece la pena?