The trust may have become irrevocable on the date of your mother's passing but the trust could still be a grantor trust if you're the sole trustee, sole beneficiary, and have authority to transfer the assets (or some of them, at least, or certain other powers granted to you) into your own name, personally (i.e., you're the "owner of the assets").
You should most likely consult with a local tax professional or legal counsel who can review the terms of the trust. If the trust is a grantor trust as to you, then you can likely dispense with filing a 1041 and report the income, expense, et al, on your own individual income tax return.
