Geetika, coupole of things here.
1) If you're in the US, 6.56% is about 1.56% higher than the prime. That's too much money in interest you're going to pay. The lmortage lending revolves around prime typically. This mean, I wouldn't lock it at 6.56% for 5 years, let alone for 30 years.
2) If you're in Canada, the prime rate is even lower. You can get far better rates in Canada than a whopping 6.56%.
3) You sure this rate is for 30 years? I've never heard of a lender who's going to give a flat interest for that long. Typically, they all give you a fixed rate for first 5 years or variable rate of a specific percentate point around the prime for up to 5 years.
4) Shop around. Historically, the mortgage lending rates have always revolved around the prime and the prime stays around 5, plus/minus.
5) If your creditworthiness is good, I think you can get better rate than 6.56%. Look for something that's less than 6%, around 5.5%. Makes a lot of difference.