While, the Catholic University of America is an actual University, consisting of many colleges, one of those Colleges is, in fact a seminary. The Theological College is not just a seminary but it is, in fact, the National Seminary. It is the only seminary under the direct guidance and authority of the United States Conference of Bishops. I went to CUA for some of my undergraduate studies and had some friends in the Theological College. While I do not believe that the Theological College accepts those not officially in formation through a diocese, you can go through the exact same degree programs as the studies are actually done through the University’s School of Theology. They do accept layity into the degree programs and you will be having your classes with the seminarians. The School of Theology is a Pontifical Faculty, meaning that the Vatican has declared all its teachings free of error and in conformity with the Catholic Faith and is, like the Theological College, is under the direct guidance and authority of the United States Conference of Bishops.
Theology courses may help you down the line, but you must remember that there is a rule (I cannot remember if it is a USCCB statute or canon law) stating that a seminarian must spend at least two years in formal formation before moving on to Theological studies. Either way, you will spend at least two years in philosophical studies within a diocesean (or religious) formation program before you move on to Theological studies.
I’ll be praying for you.
God Bless,
Br. Ben