No, it’s not bad, it’s not a sin, and you’re missing the point of prayer and bordering on superstition-
2111 Superstition is the deviation of religious feeling and of the practices this feeling imposes. It can even affect the worship we offer the true God, e.g., when one attributes an importance in some way magical to certain practices otherwise lawful or necessary. To attribute the efficacy of prayers or of sacramental signs to their mere external performance, apart from the interior dispositions that they demand, is to fall into superstition.
Prayer is:
2559 "Prayer is the raising of one’s mind and heart to God or the requesting of good things from God."2 But when we pray, do we speak from the height of our pride and will, or “out of the depths” of a humble and contrite heart?3 He who humbles himself will be exalted;4 humility is the foundation of prayer, Only when we humbly acknowledge that "we do not know how to pray as we ought,"5 are we ready to receive freely the gift of prayer. "Man is a beggar before God."6
2562 Where does prayer come from? Whether prayer is expressed in words or gestures, it is the whole man who prays. But in naming the source of prayer, Scripture speaks sometimes of the soul or the spirit, but most often of the heart (more than a thousand times). According to Scripture, it is the heart that prays. If our heart is far from God, the words of prayer are in vain.
The Rosary isn’t a magic ritual. It’s an exercise or discipline that many find useful in achieving prayer’s purpose to raise their heart and mind to God. It is not saying the prayer the ‘right’ number of times in the ‘right’ order that makes the Rosary effective. It is focusing your mind and heart on God- if you achieve that while saying any prayer (even if the words weren’t in the traditional format) you are on the right track.