playing Bass is easier but if you want to play bothtypes I would recommend starting with a normal six stringed guitar, as you will quickly get used to it and will find it easier to switch between them if you learn in this way, This is how I learned and I have had friends who learned bass first who have never really got to grips with anything else. This of course is just my opinion and it may be that you will find something different works better for you
In any case enjoy the experience of learning to play, its best to have fun with it, as perfection requires an awful lot of practice :-)