First, was this your only money in a traditional IRA, or did you have previous pre-tax (tax deductible amounts) in the traditional IRA. Because if you had pre-tax amounts, you can't do a simple conversion, it gets really complex.
Then, converted amounts in a Roth IRA have a 5 year clock. If you withdraw in less than 5 years, you don't pay income tax, but you do pay a 10% penalty for early withdrawal if you are under age 59-1/2. There is no penalty for withdrawing conversion amounts at any time if you are over age 59-1/2.