Mixing is fine for a comfort/love quilt. It will not last as long, but it will make a darling gift for a child. Just be sure to pre-shrink all your fabrics, to use a 3/8" or 1/2" seam allowance instead of 1/4", and maybe to use a shorter stitch length to reinforce the seam and prevent unraveling. To prolong its life, I would pre-wash in cold water & put a note on the quilt tag or pinned to your quilt encouraging the recipient to do the same.