Yes it is worth it!
How's this for a success story?
I left school at 16 with 2 'o' levels and 3 CSEs.
Having had some crappy jobs I went to night school to learn secretarial skills and managed to get an office job. Cue years of working my way up the ladder then taking a few years out to have my DDs.
When DD2 was 3 I went back to work very part time. Started to work my way up again but always had the idea in the back of my mind that I was a bit inadequate because I didn't have any decent qualifications.
So..... when I was 33 (and DDs were 8 and 5) I decided to try and get into Uni. I made a few phone calls late September 2002, went for an interview and ended up with an unconditional offer for a part time place. On my way home from the inteview I walked past a whole load of graduates coming out of their ceremony and thought to myself "one day that'll be me".
Just a couple of weeks later I started my course, thinking "I'll be glad to come out of this with a third". There then followed 6 years of blood, sweat and a lot of tears. While I was studying I was promoted and ended up as CEO of an incorporated charity so I had a mahoosive work load at work, a home and family to look after and my studies (I struggled so much at first that I used to have a text book in one hand and dictionary in the other 
).
Well in 2008, I was one of those graduates proudly walking from the uni in my cap and gown to the ceremony venue to get my First Class Honours degree .
Not bad for a thicko from a bog standard comp.
So beansmum my advice to you it this. Time will go just as quickly whether you study or not, but if you just stick at it those 3 years will be gone in the blink of an eye and you'll have something that no one can ever take away from you.
Good luck and keep at it (but I thank God I hadn't found MN when I was studying )