Any Catholic is free to have a devotion to Mary or not, as they feel called. For me personally, Our Lady of Fatima was instrumental in bringing me to Christ.
The only apparitions and messages to which to give any credence are those approved by the Church. Even then, since they are private revelations, Catholics are not bound to follow them.
All grace entered the world through Mary, since Jesus was born of her. All grace continues to enter the world through Mary. We are all part of Christ’s One Body, with Jesus as our Head. Mary, is the neck. She connects us with Him and Him with us. He gained His humanity from her and thus made it possible for us to be redeemed.
As the mother of Christ the King, of the Davidic line, she is the Gebirah, the Queen Mother. In Davidic royal heirarchy, the Queen Mother is granted power which may be exercised at her own discretion without consulting the King. This power comes from the King, but she exercises it. Moreover, no one gained an audience with the King without first going to the Queen Mother. Thus, we request Mary’s intercession.
I’m assuming that what you mean by ‘keeping your Marian devotion healthy’ is not allowing it to ‘slide’ into worship and idolatry. Only you know what is in your heart when you pray. You will know if you ever come close to giving Mary the worship due to God alone.
No Marian Devotion takes you away from Christ. In my experience, Marian Devotions only bring us closer to Christ. For instance, many apparitions have requested that we pray the Rosary. This is a Christ-centered prayer in which we meditate deeply on the Life of Christ in the Joyous, Luminous, Sorrowful and Glorious Mysteries. The audible prayers of the Rosary are only a fraction of the prayer that is occurring. It is a wonderful way to come to know Christ more intimately.
Here is the Catechism on Mary:
969 “This motherhood of Mary in the order of grace continues uninterruptedly from the consent which she loyally gave at the Annunciation and which she sustained without wavering beneath the cross, until the eternal fulfillment of all the elect. Taken up to heaven she did not lay aside this saving office but by her manifold intercession continues to bring us the gifts of eternal salvation. . . . Therefore the Blessed Virgin is invoked in the Church under the titles of Advocate, Helper, Benefactress, and Mediatrix.”
The term Mediatrix in itself could refer to either the objective redemption (the once-for-all earning a title to grace for all men), to the subjective redemption (the distribution of this grace to individual men), or to both. It is most usual to use it to refer only to subjective redemption, i.e. , the process of giving out the fruits of the objective redemption, throughout all centuries. We must consider whether or not the term Mediatrix applies to all graces or only to some. We will ask also about the nature of the mediation: is it only by way of intercession, that is, does Mary simply pray to her Son that he may give us grace, or does God also use her as an instrument in distributing grace.
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Leo XIII, in the text referred to, spoke of her, as we saw above, as having “practically limitless power.” St. Pius X said she was the "dispensatrix of all the gifts, and is the “neck” connecting the Head of the Mystical Body to the Members. But all power flows through the neck. Pius XII said “Her kingdom is as vast as that of her Son and God, since nothing is excluded from her dominion.” These and many other texts speak in varied ways of Mary as Mediatrix of all graces, so often that the teaching has become infallible.
