A word of advice: beware anyone who tells you to avoid AncestryDNA.
Many genetic genealogists, myself included, have had incredible success using AncestryDNA’s autosomal DNA test. Personally, several of my own major DNA discoveries have occurred though the service. Unfortunately, it has become popular among some genetic genealogists to deride AncestryDNA’s autosomal DNA test, and some recommend avoiding the service altogether.
While AncestryDNA certainly does have limitations, avoiding the service is missing out on a major opportunity and one of the largest autosomal DNA databases in the world. This is especially true for adoptees; anyone that tells an adoptee not to test with AncestryDNA (or not to test with any one of the three major testing companies) should not be assisting adoptees.