Hollywood actress Uma Thurman is desperate to retain her leading lady roles as she matures, insisting her screen skills are improving every day. The KILL BILL star, who celebrated her 36th birthday in April (06), fears she'll slip under movie-makers' radars as she gets older. But to ensure she doesn't, the actress is launching a frantic campaign to show good acting is born out of experience rather than youthful looks. She says, "Theoretically, athletes run more slowly as they get older. But actors get better. They may be less attractive - but, professionally, they grow richer and deeper."