Can i ride Royal Enfield Continental GT 650 as i am 5.8" tall and i weight 49 kg?

Yes, at 5 ft 8 in you should be able to ride the Continental GT 650, because its seat height is about 804 mm, which is manageable for many riders around your height. The bigger question is your weight and overall strength, because the bike is heavy at roughly 202 kg kerb, so low-speed U-turns, parki