Which instrument(s) should I learn? 

Have you ever wished you could play guitar, bass, saxophone, flute, violin, piano, drums or even sing? Well, the truth is you can do it all. Music is an art that can be taught to almost anyone with a little talent and a true love for music. It's helpful to try to learn one instrument to an intermediate level before taking on a second instrument.

Learning keyboard is good start because you learn some basic music theory, counting and standard musical notation which translates well to other instruments. Learning guitar can be a lot of fun but make sure your fingers are big enough and strong enough to press the strings down onto the neck of the guitar.  Consider a ukulele as a first step and you will be playing songs within a week or two. Guitar and  uke and drums can be learned  without learning to read standard music.  With guitar you can learn to strum chords to your favorite pop songs. 
Drums require a good sense of rhythm and some extra coordination to get really good.

 I always thought violin was the hardest of instruments to get through that but that seems to be just a personal opinion as everybody is different.  

If you're taking a voice, be patient and be certain to practice all your vocal exercises. Remember voices change as we get older. If you are taking up a woodwind instrument be sure you have a nice quiet place to practice as just getting a good sound  from your instrument is part of the program.

It's important to realize that to be great at any instrument, it takes years of practice. Remember, through the many hours of practice, come a lifetime of rewards.