Are all three black marks from the same stop? Has anybody taught you that locking the front wheel, especially if you don't keep the bars straight, is one of the fastest ways to crash?
Like ^^^ Chuckbear said , the over inflated tire may reduce the contact patch but has nothing to do with applying too much pressure at the brake lever. Keep practicing quick stops and forget about doing endos till you master the basics.

 

It seems to me it's much more likely that you just grabbed the front break instead of slowly squeezing it. I'm not saying that's what you did but it's MUCH more common for a new rider to slam on the front break and go down then it is because of an over inflated tire.

 

Look at the length of the skid...When the front wheel stopped turning you need to let off the brakes...and keep the bars straight. Keep your head up and look where you want to go. At threshold braking the front may howl but it is still turning. There is also weight transfer to the front. Your effort on the rear brake has to decrease as weight transfers to the front to keep from locking the rear also.
Find a quiet parking lot and practice braking in a straight line. You can try braking harder and harder till you get a good feel without worrying about traffic.