I was wondering something the other day; basically I am a 16-years-old practicing Muslim and I wear a Hijaab and Jilbaab, Al-Hamdu Lillaah, and I have learned the importance in Islaam of having good friends, Masha' Allaah my friends do have good hearts but when I am walking with them I am wearing totally different clothes from them, some are wearing the Hijaab, yet wearing fitted clothes underneath, whilst some are wearing no Hijaab and cleavage and stowage may even be showing (these are all Muslims), is this bad for me as a Muslim that is wearing a Hijaab, etc, does this represent me in a bad way?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

Indeed a person affects his friend positively or negatively that's why Islam has urged us to befriend righteous people. It is confirmed that the Prophet said: "The example of a good companion (who sits with you) in comparison with a bad one, is like that of the musk seller and the blacksmith's bellows (or furnace); from the first you would either buy musk or enjoy its good smell while the bellows would either burn your clothes or you get a bad nasty smell thereof." [Al-Bukhari and Muslim] So we advise you to keep company with righteous girls who would help you when you remember, and who would remind you if you forget. Yet, you have to be careful about dissolute girls especially if you fear to be affected by them or be led astray because of them. However, if you hope to influence them to become righteous and you do not fear being tempted by them then there is no harm in keeping company with them sometimes. However, you have to advise them and admonish them to perform good deeds. Finally, it should be noted that it is permissible for a woman when going out to wear tight clothes as long as her outer garment fully covers her (i.e. fulfills the conditions of Hijab). May Allaah make you steadfast on His true path and enable you to do good.

Allaah knows best.