Here's a little opinion of mine. I do have 2 guitars and a bass and believe me, playing bass and guitars are 2 very different styles. You need to have more strength in your fingers for playing bass. Also the scale length of the guitar and the bass is quite different, meaning the spacing between each fret is a lot more on a bass. My suggestion is that you concentrate on one first, either guitars or bass. Trying to learn both at the same time will definitely confuse your muscle memory. Just my 2 cents worth.