I am 52 yrs old, female and having a height of 1.52.3 cm. how many kilos shld. i have?

The BMI chart: Age is only used for pediatric/young adults, often calculated to age 18 or so. After this point, we only use height and wt to determine healthy vs not-healthy-wt ranges for both men and women. It is a rough estimate and provide you a guide to keep "ideal body wt" for better health. If you have specific concern about your wt/height vs age (we shrink in height with age), consult doc. Good luck.