Replying to center?

On my old atomics I had my bindings mounted a little bit behind center and they were 155 cm or something.

I got some rossi scratches the other day and they are center mounted and 174cm..

When i skied ont hem the other day i felt like i had more ski behind me than in front of me. Is this just because im not used to it or is there an easy way i could check to make sure they are mounted correctly. I tried using a tape measure but couldnt figure out where to measure to/from.