If they are intimidating, then it very likely is that they are feeling scared ... a very natural emotion for all of us when things are about to change, even when it's a change for the good, it's still scary. Since they are the "adults" they don't want to feel like they are at a disadvantage and so they are reflecting that attitude that they think will most effectively hide what they are really feeling.

If you understand that they are very likely feeling afraid, then the next step would be to figure out what they are afraid of .... lots of things come to mind regarding parents whose children are about to become independent and not all of them revolve around the child .. their lives are about to change and they may not be certain what that means to them, lonliness, lack of "purpose", fear of growing "old" .... any number of things could apply ...but if you recognize that they may be dealing with their own issues, then it may help you realize that it's not necessarily about how they feel about your choices, etc., they may be fully comfortable with your track record, but are scared that once you get a certain distance away, you may never look back ... all of us want to be loved and remembered ...

Sorry, now I'm just rambling, I totally agree with the advice given here by Lil and PF, just adding another viewpoint for you to consider. Best of luck in your bid for independence.