Are you wanting to surprise your mom or let her in on choosing fabrics? She might like the soft palette you've chosen. I think the raspberry boxes give it enough contrast if the whole pillow is to look muted in tone. I would use those together for my own mom (except switch pink out for lavender because of her preference for lavender).
However, if you're wanting to do a pillow that really lets your design take center stage, then I'd suggest, like others, to pull some higher contrast fabrics in (raspberry), or lower contrast, such as an ivory tone-on-tone . I really think the number one consideration is your mom's preferences. If she likes the fabrics, she'll love what you do with them, I'm sure.