More College?

I am crazy I think. I have found out about an online masters degree for civil engineering. I am researching it to see whether I can afford it. It has the benefits of teaching me about structural engineering and helping me get my PE license sooner. The trade off is for 18 months, I will be spending about 20 hours a week studying and 26k to make it happen while still working full time. Think I can do it? Can you help? Maybe not, but if you can, that'd be really great. At least pray that I will make a wise decision about it. I am excited about the opportunity, but I am fearful of the costs.