it's a discontinued model with no specification from schwinn or on the costco site, so we can't confirm the size. Looking at the crank it could be a 122ish length.
measure from end of taper to end of taper. ignore the threaded nutted parts.
Less than 2 months for a BB should be covered under some sort of warranty I would think, but good luck on getting costco to come through. They may have a service plan but don't count on it. 10 miles a day 5 days a week for 8 weeks is ~400 miles.