1 year working as a freelancer, no tax- still eligible?

Hi,

I had a work permit for 4 years and acquired Tier 1 visa in Jan.

The first year I had been working as a freelancer and didn't declare my income, thus I didn't pay tax. After that, I changed a job, got a permanent position and have been paying tax and NI for 4 years.

Am I eligible for ILR? or should I wait for another year?

Thanks for your help in advance.

Have you since done a tax return and paid the tax whcih is owing?

No. I haven't done it. If I pay the tax now, is it going to be OK?