Dun headache so much at the moment, since you are only asked to go for the interview. It does not mean that you will for sure get the offer, so you shd not cancel your first offer/application. Only when you have gotten a concrete offer from the second company then you need to judge which company is more suitable for you. By then, you might have already started work at the 1st company and may be able to make a better judgement if it is suitable for you.