Do they know what class you are and can prepare accordingly?
Without needing to target these theory values, which my other choices do, the linnorm can almost certainly defeat you. Using its superior flight speed it can kite your 60flight, spewing its breath weapon on you until you eventually die from negative levels. Even should you close with it, it can most probably tail strike and grapple you on the way in. This counters most of your attack charge runs. Against ranged it has good ac, a rare dr and regenaration, and it can still death curse you. In a solo fight death curse means you are checkmated no matter whAt action you take.
It also has enough sr to force your spells to 50%, excellent saves for about 60% success rate for it, and great immunities.
Your only choice would be to surprise it or fight it in doors , but it has true seeing and good perp. Indoors, with a bunch of scrolls of remove curse .
There is it's size to consider for an interior fight as well.
Unless you invested heavily in arcana, you are also unlikely to identify it or it's dr regenerAtion.
The cheese move is to force you to fight multiple opponents, even though you imply you want 1v1, and throw a horde of pale strangers at you.
For the general public who are no doubt inspired by my in depth hard hitting analysis, please hold your applause. #nerd