Since you have never played a mage before, you may want to focus on either spellcasting or conjuring. The hermetic tradition can make a monster of a combat sorceror, with high willpower and logic, focused concentration quality, and some bioware/genetech to further enhance drain.
This is the basics of my 400bp hermetic blaster:
dwarf mystic adept -- he's dedicated to blowing things up and doesn't want to make himself an astrally-active target, so I saved 5bp by giving up astral perception/projection.
B-3, A-2, R-3, S-3, C-2, I-4, L-5[8], W-6, E-2, M-5(4), Ess-5.0 -- he's built to sling big spells over and over with minimal drain, even overcasting to force 7-8 with little problem. I'd avoid maxxing an attribute out, the 25bp are not worth it and can be better spent elsewhere
Spellcasting(combat spells) 6(+2), Counterspelling 4, Dodge(ranged combat) 4(+2), Perception 2, Arcana 1, Etiquette 1, Data Search 1 -- you can drop the two specializations for another skill point, a lot of people will recommend you never take specs in character creation because they're cheaper to buy in-game with karma. These two, however, are immediately applicable and very useful.
Mystic Adept, Focused Concentration 2, Restricted Gear (cerebral booster), Aspected Magician (sorceror) and 30 other negative quality points -- more drain soaking, and try to convince your GM to use the expert aspected magician optional rule in Street Magic.
Attention Coprocessor 3, Vision Enhancement Retinal Mod 3, Damage Compensators 1, Enhanced Protein Exchange - Daredrenaline, Cerebral Booster 3 -- all standard grade, total essence cost of 1.0. This gives you +6 dice on visual Perception tests, +4 dice on your drain from the Willpower test boost and Logic augmentation, plus you can default on most logic-linked skills with some margin of success. It's not much of a leap for this character to become the group's armorer or such with minimal karma expenditure (important for a magically-active character, their powers are karma hogs for character improvement).
acid stream, boom (limited), lightning grenade (WAR!), manaball, manabolt, stunball, extended clairvoyance, increase reflexes, phantasm, bullet barrier, ice cloud (WAR!, limited), levitate -- a robust selection of combat spells with carefully selected support spells. The bp put into combat spells alone may seem like overkill, but when your job is fire support you want to make sure you're the best at it. Ice Cloud in particular is a great battlefield control spell, setting up a suppressive fire field with ice secondary effects, ten times better than mundane suppressive fire... nothing like watching people fall down and be unable to get out of the field, or being able to reposition the suppressive fire at whim.
combat spellcasting focus 3, health sustaining focus 3 -- to help you make things die, and to sustain your increased reflexes. Some people like to use force 1 sustaining foci and blow edge to get hits above the spell's force, but we house rule a limit on hits for sustaining foci equal to the force so you need a larger one.
26,500 nuyen for remaining gear-- spend it frugally. You can get more by taking the In Debt negative quality, but many GMs are tough on this negative quality.
