hi, I'm 14 and had this habit too, but I broke it, and here's how I did it!
-the reason you're feeling that you need to, is because you're so used to it. the best thing to do is NOT to quit cold turkey. know that you can sleep in her bed if you need to. that'll help.
step 1- make your room love-able! get a new bedspread, pillow, and re-decorate/arrange your furniture. that'll make you WANT to sleep in there. maybe get a night light so you feel more comfortable.
step 2- maybe you can sleep on the living room couch if you're still having trouble. that's what I did. I feel comfortable on the living room couch. actually, my mom won't let me sleep in her bed anymore. so I resorted to the couch, and I feel really comfortable on there as well. try it if you can't sleep!
step 3- before you go to bed, tell yourself this "I love my bed. I love my room. I can fall asleep in 10minutes. I have the most comfortable bed in the whole house. I can sleep in my own room"
also, don't watch TV, don't go on the computer, don't play any video games, no caffeine, and no chocolate 1 hour before bed. this will keep you awake!
try a bedside lamp. if you feel uncomfortable, turn it on!
step 4- maybe try being in your bed for a longer time each night. day 1, 30 minutes. can't sleep? go to mom's room. day 2, 1 hour. can't sleep? go to mom's room (or couch) day 3, 2 hours. STILL can't sleep? couch or mom's room. day 4, 3 hours. etc. you'll EVENTUALLY fall asleep. so just relax! maybe listen to an ipod or something.
step 5- r-e-l-a-x! lay on your back. start by relaxing every muscle in your body, from your head to each one of your toes. then, tighten them. relax them again. keep doing this. it's proven to relax people.
step 6- maybe have your mom lay in bed (YOUR BED) with you for half an hour each night. maybe you'll get used to it. having comfort from your mom isn't a bad thing at all! it shows you 2 are close.
it's better to break the habit while you can though!
step 7- if nothing above helps-just do it. even if you're uncomfortable. don't let yourself leave your room. you should get used to the idea sooner or later. you could even imagine being in your mom's bed. like pretend kinda.
and yes, you are normal. a lot of people have this problem (I did, and only fixed it 2 months ago)
I really hope these tips helped you!
good luck, sleep well!