Good on you primatives, sounds like you're well on your way!
It's a bit hard to recommend one job over the other with so little info but I'm leaning towards the helpdesk role. Are you able to provide a bit more info on the two companies? Also, don't think you have to go for the very first thing that's offered to you. Keep in mind that February is one of the busiest times for new jobs and there will be plenty of opportunities out there for you.
With helpdesk roles, my first question to the employer is whether they have a KPI for adhearance or not. If they do, they will monitor how much time you spend available to take calls. After 3 years of this, trust me, run if they say this is one of their KPI's! Need to go for a 3rd toilet break in one day, or *gasp* take a toilet break outside of your allotted time? Get ready to send an email to your team leader explaining yourself! Admittedly you get used to it but **** me if I could do it again, especially after having worked in the public sector for quite some time where SLA's and KPI's are a thing of the past (mainly due to no financial penalties being imposed for missing weekly/monthly/whatever targets).