My 20 month old daughter still uses her pacifier but...?

She'll be just fine. The main problem with pacifiers is how it affects their speech. Children who learn to talk with pacifiers in their mouths often has speech difficulties later in life. If she only has it when she is getting ready to sleep, then she is not talking, therefore no worries about her speech. As far as 'screwing up' her mouth, it takes prolong use to effect the teeth and it doesn't sound like that is her at all. Let her enjoy it!