I started on bass when I was 17 because a band needed a bassist and someone needed to sell a bass, so I was basically conned into it, I had no previous musical experience except a year playing clarinet at school and a few weeks as a drum major in the school band (ooh, how middle class). However, I got into it straight away, as it is, to be honest, the easiest of the stringed instruments to get started on, but a lot harder to get really good at.
I then got bit bored so started teaching myself cack handedly to play picky blues/alt county guitar and have been playing that in a band for the last 10 years, and although I don't think I am terrible, I have never felt as confident as I do on the 4 strings. The last 3 years relearning and learning new stuff in the new band I'm in on the bass has been a blast.
Playing both really informs the other, melodically and rhythmically, but at the end of the day, where do you feel most comfortable, leading from the front (in the limelight), or from the back (in the dark)? I personally like the fact that a lot of my friends don't know actually what a bass guitar is!
Keep playing both, but probably concentrate on one you'd be happier playing live. Probably a bit of a cliche, but if you're an extrovert, play the guitar, an introvert, the bass, or a neanderthal, the drums (apologies to all drummers I have worked with - they've all been excellent)
Tata