Those who usually seek a convalidation, it is because they married outside of the Catholic Church/parish.
The position of the Catholic Church is very clear on this matter.
SO - do we need a convalidation or not, and why or why not? It's a valid marriage in the eyes of the Catholic church, just not a sacramental one, because you're not baptized.
When the two of you become baptized, you'll be Christian and your marriage will be considered a sacramental one!
Lourdes--I have no information on what you mean by your statement that your niece was "not married in the Catholic Church." Given that her husband is non-Catholic, she may not have been required to marry in the Church.
On the matter of "marriage convalidation" in the Catholic Canon Law, it states: THE CONVALIDATION OF MARRIAGE Art. Canon Law # 1157 The renewal of consent must be a new act of the will concerning a marriage which the renewing party knows or thinks was null from the beginning. If the impediment is public, both parties must renew the consent in canonical form, without prejudice to the prescript of Canon Law # 1127 2. If the impediment cannot be proven, it is sufficient that the party conscious of the impediment renews the consent privately and in secret, provided that the other perseveres in the consent offered; if the impediment is known to both parties, both are to renew the consent. A marriage which is invalid because of a defect of consent is convalidated if the party who did not consent now consents, provided that the consent given by the other party perseveres. If the defect of consent cannot be proven, it is sufficient that the party who did not consent gives consent privately and in secret. If the defect of consent can be proven, the consent must be given in canonical form. To remedy the situation, the couple must present itself as a couple to the parish priest.
She has been baptized and she made her first Communion years ago.
Is it possible for her to receive the sacrament of confirmation while she is not married in the Catholic Church?
This is what is offered in the Book of Blessings, and it is best to assume that what the Church has prepared in its ritual books are the best practices.
I have just found out that a niece is scheduled to receive the sacrament of confirmation this fall.