She told me that my path was Karma Yoga (i.e. which I understand to mean serving the divine) rather than meditation.

Karma means literally action. I really like how Bhagavad Gita describes Karma yoga, “Karma-yogi performs action By body, mind, intellect, and senses, Without attachment, Only for self-purification.” Thus all actions are basically an exercise in mindfulness (wu-wei).

However, if you understood it as “serving the divine”, I would say that your predominant direction is Karma yoga in combination with Bhakti yoga. Now, Bhakti is traditionally regarded as “worship”, which may be somewhat vague or even misleading. Devotion would be a better word. I personally like to view Bhakti as acceptance (or letting go), which in its ultimate form is acceptance of our mortality (by letting go of oneself, or devoting oneself completely).

But — important is which path you are drawn to most.

The two other remaining major directions are Raja yoga (what is nowadays in west understood as yoga, including various forms of meditation) and Jnana yoga (path of knowledge or gnosis, including “Who am I?” inquiry).

I won’t go into details, but in the end one has to embrace all four directions, albeit not each in the same depth (the predominant direction depends on temperament of each person).

Psychosynthesis tradition uses that question as a meditation tool. They also have a series of mantra

Yes, that’s the type of inquiry I was talking about. As for those mantras — those sentences are good reminders while inquiring, but I would be careful to use them as mantras (repetitive chants/prayers), as mantras have the peculiar side effect of autosuggestion which may add another layer to pierce through or it simply preoccupies the mind and no inquiry actually happens.

The following video is a perfect explanation — it cannot get simpler than that.

And a short remark to meditation — it’s useful to train that skill as it is used during all other exercises.