It will be different for everyone but a friend of mine took 6 years and still didn't have it complete. (Between work and her 4 young kids she just didn't have the time she thought she would) Here it's a 2 year course though with a choice to get your ECE III with another 6 months and specialize in one of three areas. She ended up just going to school for 2 years and got it done that way

If you're dedicated, disciplined, determined and have the time than I think you can do it in the year!!

Oh and Another issue she had was that it was course by course and she didn't always have the money to start the new course and buy the textbooks.