A question for all the knitters..

ok I checked my gauge on my sweater..

( and no I didn't make a swatch.. and now I see why I should have?!?!)

shame shame on me

but my gauge is about 3/4" off of what it should be.....

so now what??

do I keep going and give the sweater to DJ??

or do I take it apart and use bigger needles??

the pattern says to cast on 4.00mm needles then switch to 4.5mm

so should I maybe just use 4.5 then switch to 5mm??

I don't know what to do here...

help please