You cannot RUIN a quilt I think. But it is a matter of how you feel about your work I guess. But I agree with trying a sampler first to see how you like quilting both by hand or machine. I am working on my first totally hand quilted quilt right now. I find it interesting to see how my stitching has improved from the middle squares that were done first and the later ones with more experience under my thimble. Still not something to write home about, but will be a memory for me.
Depending on the pattern and how you want to quilt the top, I say go for it and do your best.