1 John 3:1 (NKJV)
My last name, Rogahn, is of German origin. But, no matter if I am in Germany, the USA, or in some other place, my name has been mispronounced and misspelled many, many times. When I was younger and someone would incorrectly spell or pronounce my name I was quick to correct them. The problem was that no matter how many people I would talk to about how to correctly spell or say my name the problem persisted. Although people have had and continue to have a problem with my name it does not bother me because I know what my name is; it is not a problem for me because that does not change my identity.
In the Bible we learn about our true identity in Christ and who God says we are. 1 John 3:1 is one example, where we see that God has called us His children. Even if other people do not understand that or accept that, it does not change the truth about who we are. Some people may try to explain why we cannot be who we say we are in Christ, why our past should disqualify us from being in God's family, or how we do not deserve a place in God's Kingdom, but that does not change what God has said about us. The most important thing is that we know who we are and what God has called us.
God's Word is the place we need to look to find out how to correctly say who we are and what we are. If God has called us His children, then we are His children. If God has said we are a new creation in Christ and righteous in Christ then we are (2 Corinthians 5:17, 21). If God has said that we are heirs of God and joint-heirs with Christ (Romans 8:17), members of the household of God (Ephesians 2:10), and blessed with every spiritual blessing in the heavenly places in Christ (Ephesians 1:3) then that is exactly who and what we are. Know who and what you are in Christ so that no matter what anyone else says about it you know for sure who you really are.