I bought some running spikes but I'm wondering now if they're too small?
I bought some Asics Hyper Rocket Girl II's in a size 6. I normally take a size 6.5-7 depending on the make...like I wore a 6.5 in the Kayanos but a 7 in the DS Trainers.
I just checked my shoes, my trainers say they are 24cm and these spikes say they're 23cm.

But they feel REALLY snug. I'm quite aware of the fact that my toes are touching the end of the shoe when I'm standing up, but when I start leaning forward it's not so noticeable.

Is it just because they're new? Will they start to give after a few wears? I've never worn spikes before so I'm not sure?

Any help would be greatly appreciated because the person I got them off wasn't too helpful.

It sounds like they might be a bit small! Is it too late to take them back?
Spikes that are too short can cause problems because you are pushed forward in the shoes when you are running on your toes, but on the same account it can be even worse if the spikes are too long. I usually leave 10mm to the end in joggers and 5mm to the end in spikes (although I'm a size 11).
Shoes will mold to the shape of your foot but won't give you any extra length. I would go try a 1/2 size up until you can stand without feeling the end of the shoe.

I like to have a bit of room for movement, albeit not too much. My spikes are half a size bigger than my joggers, but that's possibly more about the make of the shoes (even though both are Asics). The spikes in the same size as my joggers are too snug on my feet.

Spikes are usually a bit more snug than trainers. You aren't in them for very long and it's important that they fit rather snug. Plus I always race in light weight thin coolmax socks. So they should feel snug. However, if your toes are touching the end that is too tight. You will get problems.