If you do want to stop completely, I think you need to think of how you will get her to sleep and settle her first. If you do want to stop, I’d call one of the BFing Helplines who will help you come up with a plan. The risk of going cold turkey would be Mastitis for you and upset of her.
Feeding to sleep isn’t a bad habit, in fact it’s a bit of a superpower. Right now you can feed her and get her to sleep.
Do you have a partner? If so, could they put her to bed in the evening for a few nights? You may need to go out of the house whilst he does this.
12 to 15 months can be pretty intense too with Breastfeeding and some toddlers will go back to almost feeding like newborns. It will pass. She’ll get more independent and move away from you more. Have a read of this on Kellymom 
Some other things that may help are:
Choosing one chair where you feed her, then not sitting in it, unless you are feeding her.
Offering a nice drink instead, maybe diluted fresh juice or a hot chocloate.
Wear clothes in the day that make BFing pretty inaccessible.
Get DH to take her out at on his days off. Things like swimming or the park and the library. Make sure she has something to eat and drink whilst they are out, so she gets used to not having to rely on you to sate her hunger all of the time.
Don’t offer, don’t refuse. This one worked fairly well for me. So if she is asking fir it, you do feed her, but you don’t offer it to her at any other time.
If she’s not already, put her in her own room. My DD woke fir a feed much, much less after we moved her.
Get DH to read 12 alternatives for the all night nurser
These tips should help where you stop BFing completely as it is a gradual process or you just cut down dramatically.
Milkies in the morning might help her through this too 