I don't know why, but my low e string, a 0.48, is sounding much twangier than my old guitars low e string, which is 0.48 as well.

It is also like this on the other strings, slightly, the e string and the b string are fine, all the others aren't like my old one, but aren't half as twangy.

How do I fix this?

Sorry if I sound like a complete noob but I have never really gone into this kind of a problem before.
Sorry dude, you can't fix Twang, Its viral... We can vaccinate you before you get it, but the only thing you can do now is learn some Buck Owens....

Wednesday is still very recent it's most probably that they havn't been worn in still. It could take a day or so longer just try and do some string bends.
the string type may be the problem I went through 3 sets before I found the right set. go to the shop that sells that guitar and ask them what is the best.