Take initiative

Deciding it would be better to suprise her rather than wait for her to get within knifing distance you considerd how to start:

You have 3 idea’s for a plan of attack

1) mana bolt, you can cast it twice before running out of MP but it will probably deal less damage than mana lance.

2) mana lance: you can cast it once before running out of MP. If you hit however you would stun her allowing a possible different angle of attack.

3) you can destroy/absorb organic material, you assumed this included organic squishy humans. So if you jumped up at her you might get her