Ok first of all, your T is YOUR T! Mom and Dad need to get over the credentials! If you have a bond with this T - don't feel like you need to go waltzing off to find a PhD. Talk to T about how they are being controlling and see what she suggests. If worst comes to worst, ask T about inviting them to a session to discuss this uncomfortable dynamic in her presence.

As an aside - a PhD and 20 years of experience does not equal better! A lot of things have changed in the past 20 years in the world of Psychology - they know more, training is different, there are new methods... it's not cool to generalize like that.