Maybe you're a little scared, or maybe you are completely terrified, but you've decided that you must have some answers. You deserve to know the truth of your biology like everyone else. You've considered the privacy arguments - you certainly don't want to wreck anyone's family life or disrupt their present personal relationships. Maybe you were part of a closed adoption in which one or or both birth parents explicitly requested anonymity as a condition of the placement. Maybe you were one of millions of babies who were abandoned on the stoop of a church or fire station and can understand the implicit need for anonymity as well as the fear and distrust of society or the mind-altering substance abuse that often leads women to such drastic measures. In spite of all this, you can't shake the feeling that maybe things have changed. Maybe her life has improved in the intervening years, and she now regrets the decision she made so long ago. Maybe she's never been able to escape the guilt of her youthful naivete and it has become the insufferable albatross of her life. So you've decided the agreements made between your birth mom and the state, placement agency, or adoptive parents implicit or otherwise, were not agreements with you and you are not bound to honor them. You've decided that you will find your truth.
If you've considered all of those things and haven't given up, you are a courageous survivor - a persistent soul of the highest order. But before you go ringing every bell and knocking on every door, truly prepare yourself for the worst. I've read stories of fellow foundlings who have survived lives of suffering, abuse, and heartbreak only to discover the identities of their birth parents "too late," after they were deceased. As disappointing as this is for them, I don't count it among the worst outcomes. No, I think it's worse to find one or both biological parents living and unwilling to answer questions. Knowing they've been found, refusing to acknowledge the fact and answer the most basic questions is heartless. While these adult survivors may find solace in knowing they are better off without such people in their lives, it's easy to understand how it might have been easier for them to bear had their parents died before being found. Even an outcome such as this does not quite sink to the depth of "worst" case scenario in my opinion. That designation belongs exclusively those those biological parents who, faced with the truth, deny it. Those who tell their biological children that they are wrong - I'm not your parent, I don't know who is, that DNA stuff is hogwash, don't ever contact me again. This is the worst outcome because not only have they been unable to accept the reality and consequences of their actions, they impugn your intelligence and ignore the enormous expense and energy you have undertaken to find their miserable selves. Half siblings, first cousins, aunts or uncles have tested and the results are irrefutable, and a few people will look their own flesh and blood in the eye and say, "Nope, it's not me" without so much as blinking. This stuff actually happens, and I say you have to be ready for it. Hope for the best, and prepare for the worst. If you are not a practicing member of an organized faith, become one. Whether your tradition is Christian, Jewish, Muslim, Hindu, Buddhist, or other, if you have made the decision to push forward into the unknown, you will fare much better if you are grounded in your faith whatever that may be. Now that we have that out of the way, here's my advice on finding your genetic truth.
Test with AncestryDNA first. I'm not saying 23andMe, FTDNA, MyHeritage and others are worthless, but unless you have a big budget to test them all at once, I'm saying start with Ancestry.
Join social media groups and follow pages with specailized communities.
Attach a tree to your DNA results on Ancestry (even if you're the only person in it - make it a public tree and put as many known biological relatives in it as you can) - include years of birth and death wherever possible
Upload your DNA results to GEDMatch (video instructions below)
Paste your matches from GEDMatch into DNA Painter (video instructions below).