You CAN do this! Reach your first goal, and then set a second one.
The range you listed is the healthy BMI range for a person who is 5'4", so their range is very realistic.
You have plenty of time, and you absolutely can do this!
Really! If this old chickie can, you will make your goal!
I set mini-goals during my journey. They worked really well and kept me from getting discouraged.
Keep us posted on your progress!