With Rahu in the 11th house & Ketu in the 5th house, though I am educated, I do not have a job, nor wealth, nor health. How can astrology be correct?

In Vedic astrology, no one can ever give an accurate prediction based on the position of just one planet. For that, a complete study of the horoscope (kundali) is required.

Rahu in the 11th house indicates immense wealth, and Ketu in the 5th house indicates high spirituality; this is only the general/standard prediction for that placement. However, if in the horoscope Rahu is in the 11th house and Ketu is in the 5th house, and all the other seven planets fall between Rahu and Ketu (in the direction from Rahu to Ketu), then a Kaal Sarp Yoga called Vishdhar is formed. In fact, there are a total of 12 types of Kaal Sarp Dosha.

Because of Kaal Sarp Dosha, obstacles and delays occur in a person's life progress, and it also causes hurdles and delays in marriage. Along with this, it also needs to be checked whether the other planetary combinations (yogas) in the horoscope are supportive of or conflicting with each other. When the Dasha-Antardasha of an inauspicious planet is running, favorable results either don't come at all, or come only after a delay.