My family calls me selfish for not lending money to sister

I am a 28-year-old male IT engineer, earning a decent salary. Over eight years of work, I have saved approximately VND2 billion (US$81,400) through savings and small-scale investing. This money, kept in a savings account, helps me support my mother and grandmother, who cannot work anymore. I also earn income from renting out a room.

I am currently living with my girlfriend and covering all our living costs. Our family’s financial status ranges between poor and moderately well-off, so I cannot expect any financial assistance from them for future expenses like marriage or buying a house. Marriage is thus not in my immediate plans, as I am preoccupied with numerous responsibilities.

My sister, whose income is less than mine, recently asked to borrow over VND1 billion to buy a house. She did not specify a repayment timeline, so it is uncertain—it can be five, but it can also be 10 or 15 other years until she pays me. I refused, which led her to accuse me of being selfish.

It is not that I am unwilling to help. But I think I worked hard for my savings. Besides, I need to secure funds for my mother and grandmother, especially if I lose my job in the future. Approaching 30 and in a four-year relationship, I feel the need to plan for a family with my girlfriend as well, which includes financial preparation for marriage and a house.

Nevertheless, my family focuses on my high salary and considers me selfish for not lending the money. This hurts because believing in self-reliance and not burdening others, I have prioritized others’ needs since I was 20, spending my savings on family while neglecting my own needs.

I am perplexed as to why I am criticized for not lending money to my sister and why my family expects favors and reacts negatively when they are unmet.

Am I really being selfish for thinking this way?