Batiks are cotton fabrics. ( unless you bought rayon batiks)
Softness of any quilt depends on quilt top, backing, amount of quilting, number of seams, type of batting... It all plays its part. But, yes, over time the (Cotton fabric) will soften--like those new jeans that start out so stiff, then become oh so comfy.... Is the backing batik also? What batting did you use? Is the quilt densely quilted?
A densely quilted quilt with a ( firm/ dense) polyester batting may stay ( stiff/ firm) for a long time, but will still over time, with use will soften up.
I use lots of batiks, have never had a stiff quilt ( always soft) so, not sure why yours isn't... How did you launder it? I toss in washer, warm water, detergent, gentle cycle, then toss into dryer, medium heat, regular cycle... Cozy soft, fluffy quilt comes out...