My wife, daughter, and I all have NEXUS already, so I applied on April 23 for our son, who isn't even 1 year old yet. I didn't think to apply sooner, because when the rest of the family applied in 2015, approval only took 3-4 weeks, and I didn't realize that the applications are so backlogged now.
Our NEXUS membership is useless until the newest member of our family can get it too. Not sure why it takes so long, since the baby obviously has no criminal record. There should be an expedited procedure to add a baby to a family who already has NEXUS. Hoping that it will be conditionally approved soon so we can get an interview scheduled, since we are taking a few trips later this year.