No, you are not any less a Christian because you don't speak in tongues. There are many different manifestations of the Holy Spirit: prophecy, knowledge, teaching, administration, giving, tongues, etc.
All these can also be manifested in some way even if you know not God (1Co 13:1-13), but the one undeniable proof that you have been baptized in the Holy Spirit is an abiding and complete love for God and for your fellow men.
[i]1Jn 4:7-8 Dear friends, let us love one another, for love comes from God. [b]Everyone who loves has been born of God and knows God[/b]. Whoever does not love does not know God, because God is love.
Mt 22:37-40 Jesus replied: [color=CC3300]“ ‘[b]Love the Lord your God with all your heart and with all your soul and with all your mind.[/b]’ This is the first and greatest commandment. And the second is like it: ‘[b]Love your neighbor as yourself[/b].’ All the Law and the Prophets hang on these two commandments.”[/color]
1Co 13:1-3 [b]If I speak in the tongues of men and of angels, but have not love, I am only a resounding gong or a clanging cymbal[/b]. If I have the gift of prophecy and can fathom all mysteries and all knowledge, and [b]if I have a faith that can move mountains, but have not love, I am nothing[/b]. If I give all I possess to the poor and surrender my body to the flames, but have not love, I gain nothing.[/i]
Be careful though, there are many who speak in tongues who would pridefully claim that one must speak in tongues when filled by the Spirit. Do not believe such false teaching.
BTW, welcome to the forum! :-)