Can I change it? They never taught us it had to be after a saint, so I picked a name I liked. Please advise
Your confirmation name is a fact. So, no, you cannot “change” it as far as changing the sacramental records.
There is no requirement to have a confirmation saint name.
You can certainly adopt any Saint for whom you have a fondness to be your spiritual patron.
If the name you selected is not a saint’s name then you should make it one.
No, you cannot change it. It’s a fact of history.
However, it need not be a saint’s name. It can be any Christian name.
Some names I’ve heard that are not necessarily saints’ names (but might be?)
Angel, Rosary (Rosario), Immaculata, etc.
There might actually be a saint (a canonized one) who has the name you chose. If there were something wrong with the name you chose, the pastor would not have allowed it, nor would the bishop have used it. The very fact that you were confirmed with that name is a good indication that the name itself is appropriate.
There used to be a very strong emphasis on saints names for Baptism and Confirmation. When my cousin Erin was baptized in about 1963, the priest would not baptize her by that name since it is simply the name of a country. Instead, she was baptized by her middle name which is a saint’s name. I remember well listening to the Latin ritual to hear her middle name pronounced. Now we baptize Heather’s, Madison’s, Sigourney’s etc. The rule is that the name must not be a name contrary to Christian sentiments. I suppose that unless your Confirmation name is Satan, Beelzebub, or Maleficent, you’re good to go.
Though a pious tradition, it is not requirement to pick a Saint’s name. I took my sponsor’s name at Confirmation. No, it cannot be changed.