I wouldn't worry too much - yes your cervix is supposed to rise during pregnancy, but when this actually happens can vary from woman to woman, and can be different with each pregnancy. I never checked mine so don't know when mine made the journey north, but personally I wouldn't go checking - just leave it be .
However, if it worried you - as with anything in pregnancy - speak to your MW. But just because it feels low now doesn't mean you'll miscarry.
Hope that helps x