RWY INCURSION BY A LOW TIME C172 ON RWY 8 AT FXE; FL.

Narrative

I LISTENED TO THE LATEST ATIS; RPTED I HAD ATIS AND TAXIED TO THE RUN-UP AREA. AFTER THE RUN-UP OF THE ACFT; I TAXIED TO RWY 8 AND SWITCHED TO EXECUTIVE TWR. I CONTACTED TWR; INFORMED I WAS AT RWY 8 AND REQUESTED TOUCH AND GO'S. I RECEIVED INSTRUCTIONS TO TAXI ONTO RWY 8 AND HOLD FOR TKOF. I TAXIED ONTO RWY AND HELD FOR TKOF INSTRUCTIONS. TWR RADIOED AND I WAS INSTRUCTED TO 'TURN L AND DEPART RWY.' I WAS UNSURE OF INSTRUCTION AND REQUESTED; 'SAY AGAIN.' THE INSTRUCTIONS TO DEPART THE RWY WERE REPEATED. I THEN TURNED EXECUTED L AND TAXIED OFF RWY 8. ONCE OFF THE RWY AND WAITING FOR FURTHER INSTRUCTIONS I DECIDED THAT THE TFC WAS GETTING TOO BUSY FOR MY COMFORT LEVEL. SO I CALLED TWR AND REQUESTED A NW DEP INSTEAD OF TOUCH AND GO'S. I FIGURED I WOULD GO TO THE TRAINING AREA AND PRACTICE MANEUVERS FOR A WHILE THEN RETURN FOR TOUCH AND GO PRACTICE. I WAS CLRED FOR TKOF WITH A L HAND NW DEP. I THEN RECEIVED A CALL FROM EXECUTIVE TWR INFORMING ME I HAD A 'PLTDEV' AND TO CALL THE TWR BY TELEPHONE. I THOUGHT I HAD DELAYED MY TURN TOO LONG AND ENTER POMPANO'S AIRSPACE OR THAT MY ALTIMETER WAS READING LOW AND I HAD ENTERED FORT LAUDERDALE'S AIRSPACE. AFTER PRACTICING FOR A LITTLE OVER 1 HR I RETURNED TO FXE; LANDED; SECURED THE ACFT AND CALLED THE TWR. IT WAS AT THAT POINT I FOUND THAT I HAD MISUNDERSTOOD THE FIRST SET OF TWR INSTRUCTIONS AND HAD A 'RWY INTRUSION' AND HENCE THE INSTRUCTIONS TO 'TURN L AND DEPART THE RWY' FROM WHERE I WAS HOLDING POS AT THE END OF RWY 8. I HAD THOUGHT THAT I HAD BEEN ASKED TO MOVE OFF THE RWY DUE TO A TFC SPACING PROB; NOT BECAUSE I HAD INADVERTENTLY MISUNDERSTOOD THE TWR'S INSTRUCTIONS. I DO NOT KNOW HOW I COULD HAVE MISUNDERSTOOD THE HOLD SHORT INSTRUCTIONS; BUT MY RADIO SKILLS ARE WEAK. I HAVE RECENTLY RETURNED TO FLYING AFTER MANY YRS OF NOT BEING IN THE AIR. I HAVE BEEN TAKING LESSONS AND RECENTLY RECEIVED MY BIANNUAL CHK OUT AS WELL AS MY RENTER CHK OUT FOR A LCL FBO. FORT LAUDERDALE EXECUTIVE IS A VERY BUSY ARPT AND I AM WORKING HARD TO GET MY RADIO WORK UP TO SPD.