Just speaking from experience as someone who did just that...
I would recommend that you obtain your bachelors, get a job, work for a few years (3+) and then decide if you want to go back.
Why? Well for starters a master's degree is a major investment and there is no guarantee that you'll like the first job that you ever have. I know a ton of people who have completed their undergrads, got a job in their field--and then totally decided it wasn't for them and left the field altogether. Getting a masters immediately after your UG sort of forces you to remain in that field (due to the financial commitment) without even knowing if it's for you. And believe me when I tell you, there are few things worse then being stuck at a job day in and day out that you absolutely detest, but have no choice but to stay there.
Plus, outside of a professional degree (law, medicine etc), most jobs that require a masters degree also require work experience to qualify for the salary and responsibility--work experience that most UGs don't have yet. Either way, if you get the masters directly from UG, chances are, you won't qualify for the positions that have that requirement anyway until you can gain experience at the entry level.