Hi Sobia,
Welcome to the forum!! Im handing my level 3 in tomorrow and its taken me 17 months. I was told originally told i had 3years to complete it, then 2months ago the funding for my course has been stopped and i had to have it finished by end of june, so its been a bit rushed.
Level 3 goes into depth more than level 2 because your working towards A level standard, its building on what you know and why you do it! Make sure you find out all the information about the course from your college or training centre, what it entails and how long you've got to do the course.
Gud luk, whatever you decide
fluffy bunny
p.s this site is a fantastic help if you get stuck