I am planning to buy a Seoul apartment-style villa for 550 million KRW; is 270 million KRW in capital too little?

Hello
In Namhyeon-dong, Seoul (near Sadang Station)
I am planning to purchase a 30-pyeong villa (connected to underground parking and has an elevator)
for 550 million KRW, and I have 270 million KRW in capital..
The bank says I can borrow a maximum of 230 million KRW, and for the remaining 50 million KRW,
plus 30 million KRW for acquisition tax and partial interior renovations,
a total of 80 million KRW will be borrowed from family using a promissory note.
In total, 230 million KRW will be a bank loan,
80 million KRW will be a family loan via promissory note,
meaning I will be buying this with 310 million KRW in debt.
This is my first time taking on this much debt; is it common in the Seoul/Gyeonggi area to buy a home with 60% debt..?