Tesla is playing their cards right. They will be later to market than the Bolt, but with the reveal in March 2016, they will show their car to be so superior to the Bolt that many would-be Bolt buyers will defer their order until the Model 3 comes to market.
Being first doesn't mean it's better. GM is claiming to be "first!" and to gain some cred and headlines before the hammer drops in March.
In any case, the Bolt and Model 3 are targeted at completely different markets.
I'll keep repeating it: Bolt is an econobox with an expensive battery. It's amenities and quality is good enough to keep the complaints to a minimum but despite the 200 mile stated range, the lack of a compelling long-distance charging network that adds value ("free travel for life") is an on-going problem. We've seen from LEAF sales that there's a market for affordable pure BEVs regarless of range and it will surely steal a lot of customers from Nissan until the second gen LEAF is out, and that's if Nissan can at least match the Bolt in several feature categories.
Model 3 is a BMW 3 series competitor. The massive reduction in battery costs from the Gigafactory will allow Tesla to offer a much more compelling and feature-appointed BEV than the others, even though the media keeps harping on the $35K price point as the basis of their competitiveness.
Model 3 will *start* @ $35k and go up from there with more battery options, better features and of course: Supercharger access. Expect prices to hit $55K, maybe more.
The way I see it GM made a car that hits just enough bullet points to break the psychological barrier to BEV adoption. Tesla is going after the largest middle-class luxury car: BMW 3 series.
As for the BMW i3, let's just say I wouldn't want to be in their shoes when the hammer drops. The i3 will need a lot of extra stuff to stay competitive and justify it's price when Model 3 arrives. By 2018 the i3 will probably be discontinued and replaced with an i5.
In time we might see cheaper cars from Tesla to compete in the lower end low-margin market unless they make a conscious decision to stay out of it and cede it to other like Apple does in the computer business. Time will tell.