Are We Poor?

She and I have a moderate income, especially now that She is in school full time. As such, we are rather frugal; driving older cars, renting a mother-in-law apartment, watching older tube TV's. We also live within a conservative monthly budget, which does limit our social activities.
During a recent conversation, She divulged to me that some of our friends think we are poor because we sometimes turn down social engagements, such as dinners or drinks. I asked if she thought we were poor, to which her response was "no."
It's definitely a hit to my self esteem that others view us a poor because of our lifestyle. However, we remain confident in our choices.