Hello, xtin88. A very warm welcome to you.
Since you are mentioning the D90, I am sure you are already familiar with the price of a D90. And as Rashkae rightfully pointed out, there will certainly be other 'hidden' costs and costs of future purchases that come at the heel of a DSLR. Like tripod, new lenses, accessories and such, which quite often may be even more expensive than the original camera kit itself.
Therefore, if after all these considerations you still say D90, then I am sure you must have budgeted for all these and your are actually mentally prepared. If that's the case, then do make yourself a happy owner.
My humble opinion.