it will be fine. just leave the volume low.

if you're concerned, do this:

put the volume at 0
start playing something
slowly but surely put the volume up a little
if you hear something funny (which i highly doubt you will), turn it off. unplug it.

as long as you keep the volume reasonable, no damage will occur. 35 watts is enough. some people use 10 watt tube amps on similar speakers.