Hi prettyinpeace and welcome to Scarleteen's boards!
First, I want to assuage your worries that masturbating 3-4 times per week is too much. There is not actually any set number of what is too much or too little for someone, it is entirely based on what feels right for you. If masturbation begins to interfere with other things in your life or feels completely uncontrollable that might be a time to re-evaluate masturbation habits but from what you described that doesn’t seem to be what is going on here.
Sadly, shame around masturbation and other aspects of sex and sexuality is also quite common due to different messaging society has ingrained in us growing up. One of the best ways to work through some of that shame is to do exactly what you're doing now which is asking questions and educating yourself to begin to un-learn some of the things out there. For example, 95% of adults have masturbated and continue to masturbate, so it's actually a very healthy sexual activity and the safest sexual activity there is. Fortunately, we have many articles that will give you honest, non-judgmental, and accurate information about masturbation (I'll link these at the bottom). Additionally, it can be helpful to identify where that messaging that masturbation is something to be ashamed about has come from (for example, t.v., community leaders, parents, etc.) and learn how to better approach those sources. Then, most importantly, take things slow, and have patience and compassion with yourself because it can take a while to shift the way you think about something but it definitely can be done. This article
here goes into a little more detail about this process if you are interested.
Here are those other resources I mentioned above:
After reading those articles, have more questions come up?