I play penny whistle occasionally, but not well- I only know about four tunes on it! ("Down by the Sally Gardens", The Foggy Dew" and "Skye Boat Song", plus "Boolavogue" if I'm feeling brave.) I prefer my 'C' one: not too high-pitched, so the top notes don't go skreechy.
I know what you mean about not wanting to play "Old Macdonald" etc. Maybe get a book of folk tunes to play along side the "learn to play" book? They'll be trickier, but more motivating. Airs and folksongs are usually easier than full-on jigs and hornpipes.
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You're so vain
I bet you think this sig is about you