I'd certainly change my flights. SFO has non-standard (too close) runways, which means any weather event or visibility impairment (SF fog) will cause closure of one of each runway pairs. This restricts the number of aircraft movements that can be accommodated due to the necessity of having arriving and departing flights use the same runways.

Under the best of circumstances 45 minutes may be sufficient. Add a delay due to anything causing late arrival of a smaller shuttle flight, you and your baggage are at risk of missing an international "heavy" departure that will more likely depart on time because it's based out of SFO.