How do you know you're ready?

I'm really confused and hoping someone can help me out. I've been putting off having kids now because honestly I'm 50/50 on having them. I love being around other people's kids when they are well behaved and it makes me feel so broody. Other times, I hate kids and I'm like no I'm not having any.

I'm 28, married, own our own house and both have great jobs. Problem is, I'm waiting on a promotion at work that could take 2-3 years before I can get it but if I got pregnant now and go off, someone else will automatically be in line for the job which will then set me back at least 5/6 years career wise.

I feel like I wanna get my career to the point where I'm completely satisfied first, but on the other hand, I've tried with my husband for two years in the past and nothing happened so we stopped trying so I know for a fact we will have problem when we start TTC again. I'm so confused and hoping someone can give me some sound advice. Thank you