Hey Trish — thanks for reaching out and for your interest in Events Calendar Pro.
You will NOT lose your events once you upgrade!
To be clear, you do not “replace” The Events Calendar with Events Calendar Pro — when you purchase Events Calendar Pro, you install and activate it alongside The Events Calendar. It adds the pro features to your existing calendar and site, so you leave The Events Calendar activated and all of your events remain totally intact!
Please let me know if this helps and if there’s anything else I can try to help with.
Cheers,
George