I am doing oregon back taxes by myself for the first time and I am ending up owing is that normal?

I am married filing separately with one child aged 17 and myself.
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Depends.
MFJ is almost always more favorable taxwise than MFS.
If you did not live together at all last year, or at least not at all during last 6 months, you may be eligible for HOH due to child.
Without knowing your withholding, tax bracket, can't say whether that's normal or not. Your child being 17 is no longer eligible for child tax credit, so that was a change.
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Sure.