Name Concern

My mom passed away 5 years ago and I truly believe my step-mom was put in my life to be the grandmother of my dreams.

Both my step-mom and my husband's mom have the middle name Sue and I'd love to use a variation of Sue for our next girl.

Question: my step-sister is not married and won't have kids for a long time. Would it be inconsiderate to use the name Sue since she hasn't had the chance to use it yet? We are not close and I'm not sure how to ask her about it either.