Yes you can. But problem is, you won't be well versed if you will be learning the 3 of them. You see, these 3 may be linked with each other but there are a lot of differences that one differs from the other.
If you are considering to take Web Development, it's gonna require you to have logical thinking as codes are not going to work without logical implications.
While on web/graphic design you need to have creative touch and eye for it.
Learn to assess yourself first where do you think weighs more. Which do you think are you more passionate about?