Best case she was in her late teens 12 years ago so she she is at least 30 but more likely mid-30s.
because sikong must be atleast 40 year old because she has daughter qian luo assuming her age to be around 17...........and also you must have also observed Li hanyi training with her brother Wu jie when they were young and there age difference was not more than 10 years......so assuming current age of wei ji to be 17 her sister Li hanyi must be around 27