Welcome to the forum. Is your GF from the area? Will her family be around?
Most of the social groups in NTT require a bride price to get married. The price is seen as the social value of the woman. Because of the higher social value put on the monetary value along with the extreme poverty of the region, most of NTT actually has a higher median age of marriage than the rest of Indonesia. Some areas are upward of 30 years old as the median age of first marriage. Depending upon the social group, it is not uncommon for women to have children before being married and live in an unformalized domestic partner situation before a formal marriage occurs. If anyone gives you a hard time about being unmarried, just tell them you are saving up for the bride price. Kupang is the central hub of the region with dozens of different ethnic and tribal groups from NTT represented. I agree with jstar and doubt you will have much of a problem.
Regardless of whether the bride price is paid in currency or gifts (such as livestock), it is usually borrowed, often directly from the bride's parents. This allows a higher bride price announcement and and increase in social status of the bride and her parents. The groom would pay the parents over the life of the marriage. The tradition was a plot device in an award winning Indonesian film "Marlina the murderer in four acts", in case you want to watch it on Amazon.
