Is it too late to go back to school and study engineering?

Every product I've worked on has had the product quality called into question by the customer. It's the worst question to get asked as the product manager. And sitting on the other side of the world from R&D, without know every quirk and twist of touching and using the product, all I can go on is the knowledge and history of the process (which has holes that I have to ignore), aided by the encouragement/hypnosis/打氣 from the boss which can sometimes veer into BS territory. He takes the time to get to know more of the details than most bosses, but still he sees things easier as they are because he is a boss.

The customer interaction is the most challenging part of the job because I have to talk about things I don't know for sure, but pretend I do know. And when I read customer reports issues with seemingly basic functions, I really struggle. I really do. The boss has set things up so that I should not have to answer technical queries, but sometimes like today, I have to respond to the customer directly because it affects sales or business, and I don't want to take the easy way out and let it go till night time for my HK colleagues to respond.

Every time this issue comes up, I wish I had the technical expertise to say, this product is wrong. Actually, I can probably figure out how to set up the product, if I decide it is priority enough. When would that be?