should we go?

Then weekend after next (25th 26th and 27th)
we will have about $250 extra to spend after putting $150 in savings.
And we found a resort in gatlinburg for $50 for 2 nights. (we have lots of saved up points)

MIL is cool with keeping DD while we go have 'us' time.
Buuuuttt we were supposed to originally have this weekend away in February for my birthday weekend.

Should we go now and just skip the birthday weekend or just wait?

If you feel like you need it now than go, otherwise I would wait it out so you could have a fun birthday weekend.