People also need to remember that it's not just in football where sports stars are having longer, and longer careers, look at tennis for example, it was unheard of when Agassi rejuvenated his career at 29 and continued to get to win/get to grand slam finals until his mid-30s. Now look at Federer, Nadal, Djokovic and it's becoming common place. Clearly, with more and more improvements in nutrition and training, people can extend their sporting careers.
Eriksen just turned 30 and has been given a three year contract, that feels spot on to me, pace was never a part of his game, and as Scholes and many other midfield maestros have proven, passing and vision tend not to fade. I can see him being first team for a couple of years, and a valuable squad player for a couple more after. I honestly just can't wait to see him in a jersey now.