0. Don't beat yourself up. Mens' bilogical clocks tick later than womens'. If your wife wasn't excited about it then it makes sense you would just go along without children until you are 40. Also don't let anyone tell you that kids are just a "want" or something, if children are right for you, they're more than a "want".
1. Get some feedback from professionals about whether you are mentally healthy enough to make important decisions. If not, try to get healthy before proceeding. But the default will be for them to tell you to wait and see, which closes options for you and your wife. If you get the feeling they don't really care about you and they are just giving the easy answer ("another decade of therapy at $100/hr, then ask me again"), seek another opinion or try to assess the situation yourself. Everyone has some mental issues and sometimes you need to move on with your life.
2. If you believe children are right for you, talk to your wife and bring her for counseling. If she's not on board and doesn't get there quickly, consider whether you are really right for each other. You have 40 more years together. Divorces are easier without kids, and if she doesn't want kids, then she hasn't "wasted" her child-bearing years on you, so there will be less pain.
3. If she's on board, go to a fertility doctor without delay, even while still trying naturally.
4. If it doesn't work, then you have to consider what to do next. Sometimes, trying and failing gives you a new outlook, and you'll value the relationship you have with your wife more, and move on with other meaningful pursuits. But also perhaps not, and you may still need to consider starting over with someone else. But there's a risk you will end up alone or with a bad marriage, which is pretty common.
5. Consider religion in your life regardless of what happens.