Assuming that the BA flight departs on time (or in IRROPS even departs) of course. AMS is a hugely congested hub airport and as another posted has pointed out, AMS rotations are one of the first in line to get chopped (along with CDG, BRU, EDI, MAN, GLA) when delays start due to fog, winds, strikes etc.

If the OP has bags to check and needs to go landside, AMS is also very hit and miss with regards to inbound passport control and then exit passports. My daughter flew in yesterday to AMS, landing around 10:30 and had a 1 hour wait for passport control to enter NL. I flew out of AMS last week around 15:00 on Monday afternoon and security was a breeze but exit passport check took about 45 minutes. When you add in possibly having to wait for a short while at an AA check-in line, 2.5 hours would really not do it.

My last 4 AMS rotations out of LHR/LGW (on both GA and U2) have all picked up at least 30-45 minutes delay, only last Saturday my daughter's flight was 3.5 hours late due to heavy fog in AMS.

As others have said, it's all about whether the OP has to go landside....