What's "make it" mean?

Native speaker’s answer
Rebecca
In this context, "make it" means to last or endure (for a period of time). Thus, you can understand "we'd never make it that long" to mean "we'd never last/endure that long." Ex: I tried holding my breath underwater but I didn't even make it to 20 seconds. Ex: My boyfriend and I didn't even make it to a month before we broke up.