Can you be in trouble if you don't tell the truth on the phone to police?

I did not tell the truth to police on the phone. I was subpeonad to go to court, I told my lawyer I did not tell the person on the phone the truth, I said under oath I will tell the truth. The prosecutor has told me to get a lawyer as she said she could file felony charges on me. I was not under oath on a phone call, however if I am put on the stand I will be honest. The thing is what I said was a lie I made up years ago, when I was a troubled teen. I should of never talked to anyone, an officer never came to my door and showed me any badge and identified himself. It was only on the phone.