Hi, I'm new here. I thought that it would be good to tell you where I am holding in life, and what my problem is.
I went to a normal Yeshivish(ish) high school, and mostly just chilled. I was always very close to my Rabbeim.
In 10th grade, I first looked at something on the internet, and from then it's been a struggle ever since.
I started getting serious about Yidishkeit in 11th grade, but I still had this problem. And so on in 12th grade.
I never spoke about this with my Rabbeim becaue I was embarresed, and I just assumed that they assume that everyone went through this.
Then I went to Yeshiva in EY for two years, wehrei really started learning seriuosly, and became a shtickel Ben Torah. But still, i could never get over this problem.
Now, I'm 21, Baruch Hashem still a growing Ben Torah, but I can't seem to shake this problem.
I'd like to start dating, but I think that it is smart to get some sort of handle on this thing.

Welcome You came to a good place. Many of us have gone through exactly what you describe. Nowadays there are rebbeim and mashgichim who are trained in dealing with this. Maybe find out if in your yeshiva there is someone.

Welcome welcome, 
Your story is very similar to mine and I assume many many people here. I've found that access is my weakness, if I don't have access I'm good to go. How is your filter situation? On your phone, computer, etc

Welcome!  Your story is common.  Can you elaborate on how big a "problem" this is?  Are you watching porn and masturbating every day?  Do you have good streaks/bad streaks?  How much of your life has this taken over?  How big a "problem" is it?

Check out the handbook.  It has eitzos for every level.

Welcome to the forum. Keep an open mind and have patience. Learn who the sober guys are around here and take their suggestions.