B. lambicus berliner - fermentation lag

So weeks ago I made a raspberry berliner with the sour worting method. I used L. delbrueckii and the acidity never got where I wanted it to be. I also used us-05 for the fermentation.

Currently I am doing the same process however I soured the wort with a starter I made from raw grain. The beer got very sour and tastes clean with no off flavors. (pH = 3.4). Rather then US-05 I pitched a 1.5 L starter of brett lambicus I grew over a week.

This has been sitting in the fermenter for about 36 hours with no signs of fermentation. Do I have anything to worry about?

Brett is known to lag. Most of my 100% Brett ferments have taken a couple days to take off, including Brett L. That's why you need the week long starter instead of a couple days. I wouldn't worry about it.