In your opinion. I believe that Catholic teaching does line up with Scripture and that it is Protestant teaching that is contrary to it. Are you claiming an infallibility for yourself that you are denying to the Church as a whole?
Not infallibility but Catholics, for all their claims of not personally interpreting Scripture, are no different. You also are making your own personal interpretation of Scripture.
The difference is that you throw your hat in with the Catholic interpretation because you have personally looked at it and decided that the Catholic one is correct.
Either way, whether you accept the Catholic position or a non-Catholic one, it’s STILL a decision that you have personally made as to which one is correct.
Mary was sinless.
Mary remained a virgin.
Eh, these two should do for a start.
You may now procede to post the Scripture that backs up these two statements.