hair dilema

i have shoulder length hair, but i want a change, so i was thinking of cutting it, to a length like meg ryan in you've got mail, but i'm worried that i'll have a huge fro when my relaxer comes out. I have an roundish face, and my mum says it would look funny. Then i was thinking of doing something like mel b, of the spice girls. Does anybody know what kind of hairstyle this is,and is it okay to have it done, if i got my hair straigtened 2 months ago. Any advice would be appreciated, thanx.