Is this string okay to put on the acoustic guitar?

I've had silvertone sd50 guitar for about six years but I really haven't learn to play it till now, so I haven't thought much about changing the strings. There seems to be really no problem with it except the coloring, but I am just a beginner so I thought I could be wrong. So, I've been looking at different strings to replace the old ones with, and I came across D'Addario EJ16-3D Phosphor Bronze Acoustic Guitar Strings Light, and I was wondering if this would be a smart replacement. If I change the weight of the string, would the sound change dramatically? (negatively or positively ?). Right now I have medium gauge, bronze Martin SP (...I've kept the strings that came with the guitar). Thanks in advance! :D