Myanmar opposition leader Aung San Suu Kyi took a historic oath on Wednesday to join a parliamentary system crafted by the generals who locked her away for much of her long struggle against dictatorship, ushering in a dramatic new political era.The 1991 Nobel Peace Prize winner's debut in a parliament stacked with uniformed soldiers could accelerate reforms that have already included the most sweeping changes in the former British colony since a 1962 military coup, including the release of political prisoners and a loosening of strict media controls.But the wildly popular daughter of assassinated independence hero Aung San also faces the difficulty of managing the expectations of a nation impatient for change and the hopes of Burmese who see her as a sole beacon for democratic freedom.It is unclear how rapidly she can deliver on her ambitious campaign promises, including the overhaul of Myanmar's army-drafted constitution, in a legislature dominated by former members of the military junta who ruled for nearly half a century before ceding to a quasi-civilian government last year."Only time will tell," she replied when asked by a Reuters reporter of the day's significance, as she waded through a chaotic throng of reporters on her way to the chamber where she took the oath in a shortened 40-minute session.Later, she told reporters: "I have always been cautiously optimistic about developments. In politics, you also have to be cautiously optimistic."