The best defence bangladesh had against Myanmar was international diplomacy and friends!! But now as we know USA even started military practise with Myanmar- We are alone!! we need to bring change in our military procurement policy!!
It's all part of the US encircling plan aimed to contain China's growing influence in the region, even then Myanmar wouldn't dare take US for granted over China, as the Chinese are the major arms suppliers as well as the most biggest contributer to Myanmar's economy. A more warm diplomatic ties with Beijing would would grant Bangladesh surety to some extent over a possible BD-Myanmar conflict... Moreover if I'm not wrong, Myanmar's armed forces does not have the capability to fight outside its boundaries whereas we do so no worries brother, for the near future...