It is my experience that those who ask such a question are usually looking for a way to justify their lack of obedience to what is clearly a commandment of God. I really hope such is not the case with you!
First of all, when we are baptized into Christ we become part of his body. In that sense, all Christians are part of the church universal. This does not make us part of a local church/fellowship of believers. The Bible commands disciples of Jesus to be part of a church. We are commanded not to give up meeting together (Hebrews 10:25). We are to submit to our leaders (Hebrews 13:17). We are to teach and admonish one another (Colossians 3:15). The list of commandments given in the New Testament which can only be obeyed by being part of a recongnizable local "church" is very long. By definition, a disciple of Jesus is one who has Jesus as Lord and who obeys the commandments of God. If we willfully choose to not obey God then, it is certainly possible that as a result we will not be in heaven. If this happens it will perhaps not so much be because we disobeyed the commands mentioned above. More likely it will be that if we do not become part of a church, we will almost certainly fall into sin, harden our hearts, fall away, and lose our salvation. This is what is taught by Hebrews 10:24-31, Hebrews 3:12-13 and many other passages.
To me, it is inconceivable that a person who is a Christian would willfully disobey God’s commandment to be part of a fellowship of believers. I do not believe you ought to obey this command so as to not lose your salvation, but because, if you love God, you will do what he asks you to do and because everything he commands of us will turn out for our good.