Dear Mike —
Not at all. That is fine. Her conscience must be respected and your marriage also. However, if you become Catholic and if she does not wish to continue being married to you, your marriage can be dissolved if you wish, under the Pauline Privilege (a provision St. Paul made for converts whose spouses refused to live in peace with them after conversion).
This is unlikely in your case, I am sure, but I just wanted to give you a complete answer.
God bless you both.
If you wish to go deeper, in understanding what we believe as Catholic Christians, consider buying a cheap copy of the Catechism of the Catholic Church to learn all the basic teachings and beliefs.