Answer
A student has both options available. He may either enroll in a school and pursue his studies there, or he may acquire knowledge through self-study without enrolling in any school. Getting admitted to a good school makes one's future more secure. Mediocre schools can only provide certificates. But some people build their lives through self-study alone, without ever attending school or college. The same principle applies in the spiritual realm.
You can make good progress on the path of Bhakti through chanting the Lord's name on your own, although on several other paths you cannot progress independently, and on some paths you can make slow progress by yourself. For instance, in the path of Ashtanga Yoga — Dhyana Yoga (meditation) — no one can make progress without the guidance of an accomplished Dhyana Yogi. The same is largely true for the Tantra path. In Jnana Yoga, one can make slow progress on one's own simply by studying the scriptures. However, the Lord has said in the Gita that one should approach a Tattvadarshi (a seer of Truth), a Jnani, offer prostrations, render service, and ask questions with sincerity — then knowledge is (swiftly) attained. 'Tadviddhi pranipatena pariprashnena sevaya | Upadekshyanti te jnanam jnaninastattva-darshinah' (4:34).
In Japa Yoga as well, merely chanting the Lord's name does not yield the complete result. It is not a complete remedy by itself. It must be accompanied by several complementary practices such as Bhava Samshuddhi (purification of inner feelings) and others. Therefore, the theoretical principles of Bhakti and Japa should be learned from scriptures such as the Bhagavad Gita, Ramcharitmanas, and Bhagavat Purana, and one's doubts should be resolved by an Acharya or a specialist in Bhakti. However, until one finds a suitable guide, chanting can still be beneficial — provided it is not done in a merely mechanical manner.