Lied About Knowing Excel

So I started my new job at this big office building downtown, and they told me on day one that knowing how to use Excel was pretty much a requirement. They also said it would help if I knew how to create pivot tables and charts. Well, I couldn't lie about knowing Excel completely, I've used the basics before, but let's just say my skills are more like figuring out basic formulas through trial and error than creating complex spreadsheets with ease. Anyway, on day two of orientation, there was this mandatory training session where we had to work in a team and complete some tasks. I got paired up with someone who knew Excel inside and out; she even talked about macros and VLOOKUP functions like they were the most basic things ever. I felt so dumb because I couldn't contribute much at all. To make matters worse, my boss was walking around and stopped to look over our work. He complimented her on how well she knew Excel and then turned to me with a curious expression. Thinking fast, I said something like, 'Oh yeah, I know it pretty well too!' It felt so fake as soon as the words left my mouth. I've been lying ever since. Now I spend lunch breaks sneaking off to an online course to catch up on Excel skills because I don't want anyone figuring out I lied about knowing how to use it properly.