I did a very extensive study on WiFi, which is based on the IEEE specification 802.11. Let me be very clear about it. IT IS NOT SECURE! Any personal information on your computer is exposed. If you have names, addresses, account numbers, PIN's SS numbers or anything else that can be traced to you through the internet, you run the very real risk of Identity Theft. The very least that can happen is your bank account can be emptied. Worst case is your whole life will be spent correcting misinformation about you in every credit situation, your mortgage, your social media...the list is endless. But not the problems. It can haunt you for years and ruin your credit, not to mention employment possibilities.
Removing ALL personal info on your computer is a good first step if you insist on using WiFi.