Welcome to the forum, Chris!
It is not bad to cultivate jhana, but one must be careful not to get addicted to “jhanic pleasures”. As I mentioned above, “Jhanic states correspond to the mental states in the brahma realms. The first four jhanas correspond to the rupavacara brahma realms and the higher jhanas correspond to the arupavacara brahma realms.”
The end result of cultivating jhana is having a rebirth in a brahma realm. Just like the human realm, those brahma realms are also temporary.
– However, if one cultivates jhana, AND THEN contemplate on the unsatisfactory nature of them, THEN one can make progress towards Nibbana (nirvana is the Sanskrit word).
Also, you may want to read the post, “Anicca, Dukkha, Anatta – Wrong Interpretations“.
– Anicca is not “impermanence” and anatta is not “no-self”.
– What one should focus on is the unsatisfactory nature of even the higher realms (human, deva, brahma). All those are not permanent and have finite lifetimes. Then, one maybe even reborn in lower realms, including the animal realm), and that is where real suffering is.
– Some people automatically attain jhana while contemplating the anicca, dukkha, anatta nature. For some others, it is virtually impossible to attain jhana even with practice. It is mainly a samsaric habit. Those who had cultivated jhana in recent past lives can easily get to jhana; see, “Samādhi, Jhāna (Dhyāna), Magga Phala“.