Last year I sped up amazingly. This happened for two reasons. First, I skied 50 days during the season, and the hours on snow built confidence and skill.
Second, I bought a new pair of skis. All the guys I ski with said I shouldn't buy them because they were too stiff for me to bend. Well, let me tell you..... they were wrong. Go fast enough and they will bend because of the build-up of forces under the foot!
These skis rock! Suddenly I discovered that I could go fast and not panic, because the skis didn't wobble at speed as did the old ones. I could all of a sudden begin to teach myself to handle the speed, whereas before I was braking all the time because the skis just wouldn't stay stable at speed.
So the change in skis allowed me to go fast without wobble/chatter; the number of days on snow gave me the opportunity to learn to handle that speed.
The old skis were short (154), had a tight slalom-style turn radius of 12 meters, and a core of foam. Nobody told me that I couldn't keep up with the fast boys on these skis, but it couldn't be done. They were made to turn often since they were slalom skis, and thus go slow. Going fast requires turning less often.
The new skis were a bit longer (160), have a longer GS-style turn radius of 16 meters, and a core of titanium. The titanium keeps them from shaking at speed. The longer turn radius (very important!!! Why don't they tell you about this in the shops???) allows me to make longer turns and thus go faster. If these skis had a turn radius of 21m I'd really be scary.
It's the turn radius, not the length of ski, that really determines its "speed". Length depends on your weight more than anything else, plus what you want to do on the snow.
I hope this info will help. What kind of skis do you ski on?