age is catching up?

I've been having this feeling for some time now.. sigh... i've seen my ex-schoolmates got married, delivered their 1st child and then the next and the next..

It got me thinking and having this mixed feelings.. my question is... do i want to be married / get into a serious relationship?.. again..

I actually loved getting married.. not of the marriage proposal or the lavish wedding or the honeymoon.. i just loved the commitment to someone i love.. to be able to call him my husband / hubby.. growing old with him, waking up beside him everyday, to know that he loves me back, and be loyal and faithful..

But since what happened, it really got me thinking.. do i still want to commit seriously and 100% to someone again? i don't know if i could take it again, to have my heart broken to pieces..

Sometimes i do wonder, should i follow my heart? or my mind? my mind keeps telling me to protect myself, that i do not need to go through another heartbreak, that i am doing good without a commitment.. but my heart is telling me differently..

Is it that my age is catching up? that my biological clock is ticking away.. and that scares me?? hmmmm.... i don't know.. i don't want to think about having kids first when i don't even know what i want..

So should i take a risk and open up for a relationship?