Bit of a clarification for a confused CMDR. There are two types of FTL (faster than light) travel - in-system and between systems.
In-system flight, aka Supercruise.
This is the mean to travel vast distances within given star system. Normally your ship can achieve few hundred m/s of speed. Flying 728 Ls (light seconds) distance would take you weeks and months. To skip that ED enables you to enter "Supercruise" - special mode in which your speed is measured in "c", speed of light. At first it's in fractions of "c". The more you fly uninterrupted (gravity fields from stars and planets slow you down), the higher "c" count gets. Max is 2001c, afaik, which means 2001 times faster than speed of light. Usually you won't get that far to see those values, expect some cases. With Supercruise covering those 728 Ls distance takes mere few minutes.
Between system flight, aka "Frame Shift Drive" (Friendship Drive)
Ok, in-system flight we covered, but how to travel between stars? When you open galaxy map and select a star, be it close or far away, you get distance to that star given in LY - light years. Given that you can reach Supercruise speed of 2001x the speed of light, going to the next star 5 LYs away would take you... about a year real time. To solve that we have "Frame Shift Drive" that allows us to travel stellar distances within seconds (in fact this is hidden in the plain sight loading screen - observe how you're unable to interact with your ship panels while in transit). Frame Shift Drive range comes out directly from your ship's FSD module, the better, the farther you can jump. Add engineering and another module - guardian booster, and you can increase your range considerably. Stock Imperial Clipper has ~8 LYs of range. Lightweight build with top FSD, with engineering and booster has nearly 52 LYs.
Anyway, got sidetracked. From what you wrote looks like you engaged Supercruise (in-system flight mode) instead of FSD mode. Check your key bindings and press "the other left" button to make stellar jump.