I think it's awful, sorry. It's trendy, made up sounding, immature, rather trashy and yet another name with -lyn on the end (I even saw Faithlyn the other day) and will date her to this period in time.
I don't know what spelling is best:
Shaelyn has the trendy -ae- in it
Shailyn is slightly better but as someone pointed out could be pronounced SHY-lin.
Shaylyn I'm not keen on the -yly- part, that is very immature/trendy IMO
Probably Shailyn.
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Louise x
~*~Top Names~*~
Charles Frederick & Isabel Primrose