Financial projections of a startup are generally wildly inaccurate no matter how hard you model them. And you do not have stable positive cashflow to calculate EBITDA. Any sort of DCF or multiple method is basically useless until you are regularly generating hundreds of thousands of dollars.
The more fundamental mistake is that you want to offer a valuation to investors. Many startups fall into this trap. Do not do that. Ask them to offer their fair valuation instead, and compare what different investors offer you. Just how you should have the terms in mind but not offer a termsheet - wait for theirs. Otherwise, you run the real risk of ending up with worse terms than what they might have offered to begin with.
Of course, valuation is not the only criteria for selecting investors, and you may chose to go with an investor who offered you a lower valuation but brought more benefits (deeper domain expertise, better connected, better lead, etc). Same concept applies to liquidation preference, voting rights, etc.
Factors that affect your valuation at this early stage include your and your co-founders past track record, team composition, project stage, current traction, current sales, future expectations/projections (remember, they are looking for unicorns so if you project a 2-3x return for them you are out), ability to execute your idea, good chemistry, whether some similar project recently raised an obscene amount or showed great success (VCs love to jump on the bandwagon), mood of the VC, and alignment of the stars.
$2m is also an amount that could conceivably be raised from angels and/or via convertible notes. You would need a strong and well-connected lead investor for this though. And it's unlikely that you can raise so much on a capless note, so the discussion about pre-money valuation will just turn into an equivalent discussion about pre-money cap.