What you describe does not sound abnormal for a young person considering a vocation or otherwise serious about the faith. The word “lunatic” seems to have a bit stronger connotation than the more typical “fanatic” that I have more often heard but that may just be my reaction to a particular word choice.
When you say “altar”, I presume you are talking about a devotional area with various objects of piety…not an actual altar such as in your parish church. Before I went to seminary, I had a prayer corner that others would have certainly described as somewhat elaborate. Of course, my contemporaries who were not aspiring to be seminarians had rather elaborate displays of sports related collections, trophies, medals and posters and such, as I remember. They could talk about statistics and such at considerable length and well beyond my interest or ability to keep up. My area of enthusiasm was different from theirs but the level of intensity may not have been that different, reflecting back after all these years.
I have certainly known young men and women who have devoted a great effort and deployed elaborate resources over a long period of time to attain something they were passionate about – in terms of hobby or sport or school or a future career path or whatever they were passionate and motivated about…including the faith.
There is a zeal and enthusiasm that marks our youth…perhaps it is that joined to a difference in the manner of expression of personal piety between you and your mother that your mother is seeing and remarking on. I can’t really know.
Over the years as a priest, I have gone into the homes of many people and encountered all sorts of elaborate displays memorabilia collections, art collections, and the manifestations of various other hobbies, if that helps relative to your devotional space.
Not knowing you or your situation, I can’t really give you much advice on this topic beyond the obvious…if you are functioning in your nurse’s training and clinical practicums and you have friends with whom you relate and who relate to you with ease and no disquiet and the medical professionals you interact with as a student nurse are not raising alarms, that would all seem to point toward the reality that you are not a lunatic.

Family members will some times speak very freely in their communication and use terms that can seem blunter than they really mean.
I assume, though, if you are seriously considering a vocation to the priesthood that you are in dialogue with a priest and have, perhaps, even reached out to a vocation director. Such a person would be in an excellent, even ideal, position to gauge any cause for concern and could alert you if there really is something problematic or troubling.
There actually is something radical in a choice to leave “father and mother, wife, children and property for My sake and the sake of the kingdom,” as Jesus said. One unquestionably makes many sacrifices, if one pursues a vocation to priesthood and/or religious life. It is not just another career choice. It is a life.
I will just add that your training as a nurse could be a very great blessing, particularly if you discern a vocation to religious life.
God bless you. I will be praying for you. May the Lord show you His will for you and for your life.